!e  oenes, 


H,  Baili?" 


®(|E  ^.  ^.  ^iU  pbrarg 


^mrtl;  Carolina  ^tate  College 

5MS 


This  book  is  due  on  the  date  indicated 
below  and  is  subject  to  an  overdue 
fine  as  posted  at  the  circulation  desk. 


EXCEPTION:  Date  due  will 
earlier  if  this  item  is  RECALLED. 


11  be  I 
.ED.  I 


XLbc  IRural  Science  Series 

L.  H.  BAILEY,  Editor 


THE  SWEET  POTATO 


Edited  by  L.  II.  Bailey 


The   Soil.     King. 

The   Sprayikg  of  Plants.     Lodeman. 

Milk    and    Its    Products.     Wiiiff.     Enlarged   and   Revised. 

The  Fertility  of  the  Land.     Roberts. 

The  Principles  of  Fruit-growing.  BwUey.  20th  Edition, 
Revisfd. 

Bush-fruits.     Card.     Revised. 

Fertilizers.      Voorhees.      Revised. 

The   Principles  of  Agriculture.     Bailey.     Revised. 

Irrigation  and  Drainage.     King. 

The   FaRiMSTEAd.     Roberts. 

Rural  Wealth  and  Welfare.     FairchUd. 

The  Principles  of  Vegetable-gardening.     Bailey. 

Farm  Poultry.      Watson.     Enlarged  and  Revised. 

The  Feeding  of  Animals.  Jordan.  (Now  Rural  Text- 
Book.) 

The  Farmer's  Business  Handbook.     Roberts. 

The   Diseases  of  Animals.     Mayo. 

The  Horse.      Roberts. 

Ho\v  TO  Choose  a  Farm.     Hunt. 

Forage  Crops.      Voorhees. 

Bacteria  in  Relation  to  Country  Life.     Lipman. 

The  Nursery-book.      Bailey.      (Now  Rural  Manual  Series.) 

Plant-breeding.      Bailey  and  Gilbert      Revised. 

The  Forcing-book.     Bniley. 

The   Pruning-book.     Bailey.      (Now  Rural  Manual  Series.) 

Fruit  Growing  in  Arid  Regions.     Paddock  and  Whipple. 

Rural  Hygiene.     Oyden. 

Dry-farming.      Widtsoe. 

Law  for  the  American  Farmer.      Green. 

Farm  Boys  and  Girls.      McEeever. 

The  Training  and  Breaking  of  Horses.     Harper. 

Sheep-farming  in  North  America.     Craig. 

Cooperation  in  Agriculture.     Powell. 

The  Faum  Woodlot.      Cheyney  and  Wentlvng. 

Household  Insects.     Berrick. 

Citrus  Fruits.     Coit. 

Principles  of  Rural  Credits.     Uorman. 

Beekeeping.     Phillips. 

Subtropical  Vegetable-gardening.     Rolfs. 

Turf  for  Golf  Courses.     Piper  and  Oakley. 

The  Pot.\to.      Gilbert. 

Strawberry-growing.     Fletcher. 

Western  Live-stock  Management.     Porter. 

Peach-growing.     Gould. 

The  Sugar-beet  in  .Vmerica.     Harris. 

Pork-production.     Smith. 

The  Development  of  Institutions  Undee  Ibbigation. 
Thomas. 

Landscape-gardening.     Simonds. 

Commercial  Apple  Industry  of  North  America.  Folger 
and  Thomson. 

The  Sweet  Potato.     Hand  and  Cockerham. 


THE  SWEET  POTATO 

A  Handbook  for  the  Practical  Grower 


BY 

T.  E.  HAND 

AND 

K.   L.  COCKERHAM 


ILLUSTRATED 


Jl3eto  gotk 

THE  MACMILLAN  COMPANY 
1921 

All  rights  reserved 


^^^\. 

<,^^ji 


Copyright,  1921, 
By  the  MACMILLAN  COMPANY 


Set  up  and  electrotyped.     Published  January,  1921. 


CONTENTS 


CHAPTER  I  PAGES 

Origin  and  Descbiption  of  the  Swb:et  Potato   ...  1-7 

Description 3-5 

Botanical  classification 5-7 


CHAPTER  II 

Impobtance  and  Distribution 8-19 

Distribution 10-15 

Climatic  requirements  and  soil  types 16-19 

CHAPTER  III 

Utilization  of  the  Sweet  Potato 20-53 

As  food  for  man 21-25 

Composition  and  food  value 21-25 

As  food  for  domestic  animals 25-33 

Sweet  potato  silage 28-30 

Roots 30-32 

Vines 32-33 

Manufactured  products  of  the  sweet  potato  .            .  33-46 

Dehydrated  and  desiccated  sweet  potatoes      .      .  34  -  3S 

Sweet  potato  flour 38 

Sweet  potato  pie  product 38 

Sweet  potato  chips 39 

Sweet  potato  sugar 39 

Starch  manufacture 39-41 

Alcohol  manufacture 41-42 

Sirup  from  sweet  potatoes 42-45 

Canned  sweet  potatoes 45-46 

Domestic  cooking  of  sweet  potatoes 46-53 

Baked  sweet  potatoes 47 

Browned  sweet  potatoes 47 

Fried  sweet  potatoes 47 

Candied  sweet  potatoes 48 

Sweet  potato  biscuit 48 

Sweet  potato  bread 48 

Sweet  potato  muffins 49 


N.  C.  State  College 


vi  Contents 

PAGES 

Sweet  potato  salad 49 

Sweet  potato  peanut  croquettes 49 

Baked  sweet  potato  custard 50 

Sweet  potato  a  la  Agnes 50 

Sweet  potato  with  raisins  and-  marshmallows  50 

Sweet  potato  devil's  food 50-51 

Sweet  potato  drop  cookies 51 

Boiled  sweet  potatoes 51 

Sliced  and  baked  sweet  potatoes 51 

Riced  sweet  potatoes 51 

Sweet  potato  flour 52 

Flour  No.   1   from  tlie  raw  potato 52 

Flour  No,  2  from  cooked  potatoes 52-53 

Flour  No.  3  from  pulp 53 

Sweet  potato  starch 53 


CHAPTER  IV 

Pbopagation 54-89 

Selecting  seed    (tubers)         56-61 

For  disease  control 57-58 

For  yield  and  quality 58-60 

Production  of  seed  potatoes 60 

Seed  treatment 60-61 

The  plant-bed 62-80 

Location 62-63 

Preparation  of  the  plant-bed 63-64 

Open  beds 64-65 

Coldframes 65-67 

Hotbed  —  manure-heated         67-69 

Hotbed  —  flue-heated  69-71 

Hotbed  —  pipe-heated         71-72 

Other   types   of   hotbeds 73 

Bedding        '^^ "  I* 

Covering  for  seed-beds 75-76 

Care  of  the  plant-bed 77-80 

Drawing   the   plants 80-82 

Use  of  vine-cuttings 82-84 

The  commercial   plant  business 85-89 

Field    methods 86-87 

Office    methods         87-88 

Advertising 88-89 

CHAPTER  V 

TILJ.AQE,   Fertilizing  and  Rotation 90-119 

Preparation   for   planting 90-91 

Distance  and  method  of  planting 91-92 


Contents  vii 

PAGES 

Setting  the  plants  in  the  field 92-93 

Cultivation         93-96 

Irrigation 96 

Fertilizers 96-112 

Kinds   of   fertilizers 99 

Function  and  form  of  plant-foods 99-103 

Commercial    fertilizers 103-105 

Home-mixing   of   fertilizers 105-107 

What  fertilizer  to  apply 107-108 

Humus 108-109 

Green-manures         109-110 

Other   materials   as  fertilizers 110-112 

Application  of  fertilizers 112 

Rotation 112-118 

Plant-food 113-114 

Root   excretions 114-115 

Mechanical  effect  on  soil 115 

Insect,  fungous  and  weed  enemies 115-116 

Rotation  to  be  used 116-118 

Conclusion 119 


CHAPTER  VI 
Vabieties 120-136 


CHAPTER  VII 

Insects  Affecting  Sweet  Potatoes 137-154 

The  sweet  potato  flea-beetle 137-139 

Tortoise   beetles 139-143 

The   two-striped   sweet  potato  beetle 140 

The  black-legged   tortoise  beetle 140-141 

The  golden  tortoise  beetle 141-142 

The  mottled  tortoise  beetle 142 

The  argus  tortoise  beetle 142-143 

Control  of  tortoise  beetles 143 

Saw-flies 143-145 

Sweet  potato  weevil 145-154 

Description         147-148 

Life  history 148-152 

Control   152-154 


CHAPTER  VIII 

Diseases  of  the  Sweet  Potato 155-169 

Stem-rot  (wilt,  blue-stem) 156-158 

Control  of  stem-rot 157-158 


iii  Contents 

PAGES 

Foot-rot 158-159 

Root-rot 159-160 

Black-rot    (black-shank) 160-162 

Scurf   (soil-stain,  rust,  Jersey  mark) 162-163 

Leaf-bliglit 163 

Leaf-spot 163-164 

White-rust   (leaf-mold) 164 

Soft-rot 1G5 

Ring-rot 165-166 

Dry-rot 166 

Java    black-rot 166 

Charcoal-rot 167 

Control  of  storage  rots 167-169 


CHAPTER  IX 

Insecticides,  Fungicides  and  Spray  Machinery  .  170-176 

Insecticides    and    fungicides 170-173 

Spray   machinery 174-176 

Dusters 175-176 

Nozzles,   hose,  and  fixtures 176 


CHAPTER  X 

Harvesting  and  Storage 177-206 

Storage        179-206 

Essentials  in  keeping  sweet  potatoes 180-184 

Advantages  of  the  storage-house  over  the  bank   .      .  185-189 

Construction  of  the  storage-house 189-198 

Operation  of  the  storage-house 198-201 

Outbuildings    for    storage-houses 201-202 

Commercial   curing-houses 202-203 

Banking        203-206 

CHAPTER  XI 

Preparation  for  Market 207-237 

Market    requirements 207-221 

Varieties 208-210 

Selling  period 210-212 

Containers 212-221 

Proper  production 221-226 

Quality 222-223 

Grading         223-225 

Quantity 225-226 

Storage 226 

Packing  operations 226-229 


Contents  ix 

PAGES 

Proper   transit      229-237 

Choice  of  car 230-233 

Packing  in  car 233-237 

CHAPTER  XII 

COMMEKCIAL  DiSPOSAI,  OF  THE  SWEET  POTATO    ....    238-256 

Markets 240-247 

Home  markets 241-243 

Foreign   markets 243-246 

Advertising 246-247 

Selling  agencies 247-252 

Commission    house 247-251 

Cooperative  shipping 251-252 

Selling  methods 252-256 

Acknowledgments 
It  is  desired  to  give  acknowledgment  to  the  following  sources, 
from  which  figures  have  been  adapted  for  use  in  this  book:  The 
United  States  Department  of  Agriculture  for  Figs.  2-7,  14-34,  40- 
50;  John  Deere  Plow  Company,  Figs.  8-11;  Virginia  Truck  Ex- 
periment Station,  Figs.  12-13;  B.  C.  Jarrel  Company,  Figs.  35-38; 
Mississippi  Experiment  Station,  Fig.  39. 


i 


PLATES 


Plate         I.     A    commercial    sweet    potato    bed    in    Texas 

Frontispiece 

FACING  PAGE 

Plate       II.     Fifty-acre  field  of  sweet  potatoes,  Thomasville, 

Georgia.      (Courtesy  Clark  Plant  Co.)    .      .      30 

Plate     III.     Sweet  potato  field  operations 56 

(After  U.  S.  Dept.  Agr.) 

Plat^"     IV.     Varieties  of   sweet  potatoes 86 

y  (After  U.  S.  Dept.  Agr.) 

Plate        V,     Diseases   of   sweet   potatoes 126 

(After  U.  S.  Dept.  Agr.) 

Plate      VI.     Sweet  potato  foot-rot 15S 

(After  U.  S.  Dept.  Agr.) 

Plate    VII.     Sweet  potato  diseases 188 

(After  U.  S.  Dept.  Agr.) 

Plate  VIII.     Sweet  potato  diseases 214 

(After  U.  S.  Dept.  Agr.) 


X 


THE  SWEET  POTATO 


CHAPTEE  I 

ORIGIN  AND  DESCRIPTION  OF  THE 
SWEET  POTATO 

Foe  many  centuries  the  inhabitants  of  the  warmer 
countries  of  the  world  have  recognized  the  usefulness 
of  the  sweet  potato  as  a  source  of  food.  Thus  Bret- 
schneider  writes  ^  that  the  plant  "  was  described  in 
Chinese  books  a  long  time  before  the  discovery  of 
America,"  in  the  third  or  fourth  century  of  our  era.  It 
was  early  an  important  cultivated  plant,  the  roots  of 
which  supplied  the  place  of  com  in  Southern  China. 
The  root  was  said  to  be  reddish  and  as  large  as  a  goose 
egg.  Bretschneider  identifies  the  plant  with  the  sweet 
potato. 

Although  the  exact  origin  of  the  sweet  potato  is 
doubtful,  its  widespread  cultivation,  which  in  range 
compares  favorably  with  that  of  such  plants  as  tobacco 
and  maize,  argues  for  it  antiquity  of  many  centuries. 
The  aborigines  are  said  to  have  recognized  such 
marked  similarity  between  the  sweet  potato  and  the 
Irish  potato  that  they  called  them  by  the  same  name, 
though  they  are  not  only  very  different  species,  but  the 

1  Bretschneider,  "  Study  and  Value  of  Chinese  Botanical  Works," 
p.   13. 

1 


2  The  Sweet  Potato 

sweet  potato  is  a  true  enlarged  root  while  the  Irish  potato 
is  a  tuber  of  underground  branches  or  rhizomes.^ 

Although  cultivated  perhaps  more  widely  in  the  New 
World  than  in  the  Old,  the  sweet  potato  now  plays  a  part 
in  the  vegetable  calendar  of  gardeners  in  every  country 
within  or  near  the  tropics  and  of  recent  years  has 
become  of  considerable  commercial  importance  in  several 
regions  of  both  North  and  South  America. 

The  definite  origin  of  the  sweet  potato  has  been  much 
investigated  and  discussed  for  many  years  and  there  is 
much  diversity  of  opinion  on  the  subject.  Although 
there  are  arguments  for  both  its  American  and  Oriental 
origin  as  well  as  the  possibility  of  its  being  indigenous 
to  both  the  eastern  and  western  hemispheres,  much  must 
be  learned  before  the  question  can  be  definitely  and  con- 
clusively decided.  The  available  evidence  in  favor  of 
American  origin  at  the  present  time  seems  to  be  pre- 
ponderant, and  this  theory  is  the  one  most  popular 
among  American  agriculturists. 

The  tuber  is  now  widely  distributed  in  all  tropical 
regions  and  is  being  considerably  used  in  the  eastern 
countries,  and  by  some  writers  who  contend  that  it 
belongs  to  both  hemispheres  is  "  thought  to  have  been 
much  used  by  the  ancient  Chinese,"  although  the  food 
article  referred  to  may  have  been  the  Chinese  yam. 

De  Candolle  says  that  Clusius  (about  1600)  was  one 
of  the  first  writers  to  mention  the  sweet  potato  and  he 
quotes  the  latter  as  saying  he  had  eaten  the  product  in 
the  south  of  Spain,  where  it  was  supposed  to  come  from 
the  New  World. ^     Historians   tell  us   that   Columbus 

1  De  Candolle  gives  Turpin  in  "  Mem.  du  Museum,"  Vol.  XIX, 
Plates  1,  2,  .5,  credit  for  having  clearly  shown  these  facts. 

2  De  Candolle,  "  Origin  of  Cultivated  Plants,"  54. 


Origin  and  Description  of  the  Sweet  Potato  3 

carried  sweet  potatoes  to  Queen  Isabella  among  his 
other  collections  from  the  New  World.  The  sweet  po- 
tato is  not  mentioned  among  the  agricultural  products 
of  the  anciently  famous  valleys  of  the  Tigris  and  the 
Euphrates  rivers.  It  is  hardly  possible  to  suppose,  had 
it  been  indigenous  to  the  Old  World,  that  the  plant 
would  not  have  been  grown  in  these  regions  when  its 
characteristically  hardy  reproduction  and  ease  of  trans- 
portation are  considered.  Furthermore,  philologists 
have  found  no  definite  Sanskrit  name  for  the  plant  and 
although  cultivated  in  India  at  the  present  time  few 
kinds  are  known  there  and  those  that  are  cultivated 
seem  to  differ  somewhat  from  the  plant  as  known  by  us. 
The  plant  was  not  cultivated  by  the  Arabs,  Romans  or 
Turks  even  a  century  ago. 

DESCRIPTION 

The  sweet  potato  plant  is  a  perennial,  although  com- 
monly grown  as  an  annual.  It  is  a  trailing  vine  of  the 
morning-glory  family  which  strikes  root  freely  at  the 
joints,  bearing  leaves  that  vary  greatly  in  shape  accord- 
ing to  the  variety.  This  characteristic  variation  in  leaf 
shape  furnishes  an  important  means  for  the  classifica- 
tion of  varieties.  Although  in  general  contour  re- 
sembling those  of  the  common  morning-glory,  the 
leaves  are  of  three  types,  entire  and  not  lobed,  shoul- 
dered and  lobed,  and  deeply  cut  and  lobed.  The 
length  of  the  vine  varies  greatly,  some  varieties  produc- 
ing very  long  luxuriant  stems  while  others  have  a 
decided  bushy  or  "  vineless "  habit  of  gro"wth.  Var- 
ietal influences  also  cause  considerable  variation  in 
color  tint  of  vines,  leaf-stems  and  in  structure  of  the 


4  The  Sweet  Potato 

leaves  themselves.  Variation  is  also  common  in  the 
prominence  and  abundance  of  leaf-veins. 

Flowers  and  seed. —  Although  rarely  producing 
flowers  and  less  frequently  maturing  perfect  seed  in  the 
sweet  potato  producing  areas  of  the  United  States,  occa- 
sionally a  small  bell-  or  morning-glory-shaped  bloom, 
with  a  purple  throat  and  white  margin,  may  be  noticed 
in  commercial  fields.  Matured  seed  may  be  produced 
if  the  gTowing  period  "is  prolonged  by  the  use  of  artificial 
means.  These  seeds,  however,  are  unreliable  for  use  in 
perpetuating  varieties  as  the  resulting  plants  cannot  be 
depended  on  as  coming  true  to  the  mother  plant.  In 
fact,  they  may  differ  widely  among  themselves.  This 
characteristic  enables  the  production  of  new  varieties  by 
selecting  strong  and  prepotent  offspring. 

Tubers. —  The  sweet  potato  as  known  to  commerce  is 
an  enlarged  tuberous  root.  In  nature  this  root  serves 
as  an  organ  for  the  storage  of  food,  to  be  used  in  nour- 
ishing the  young  shoots  from  which  the  plant  is  ordinar- 
ily propagated,  but  man  has  converted  this  stored  mate- 
rial to  his  own  use.  This  edible  tuber  is  much  prized 
throughout  the  warmer  parts  of  Asia  and  the  Americas 
as  well  as  to  considerable  extent  in  other  semi-tropical 
and  tropical  countries  as  a  staple  article  of  food.^  The 
tubers  are  variable  in  shape,  size  and  color  as  well  as  in 
food  value  and  chemical  constituents.  Some  are  long 
and  cylindrical  while  others  are  short,  thick  and  blunt 
at  the  ends.  (Plate  IV.)  The  skin  may  be  pink,  yel- 
lowish or  dull  straw  color,  purple,  red  or  whitish  in 
color.  The  flesh  is  variable  also  in  color,  quality, 
moisture  and  texture.  These  tubers  (unlike  the  com- 
mon or  Irish  potato)  do  not  bear  definite  eyes,  but  are 
formed  in  underground  clusters  immediately  beneath 


Origin  and  Description  of  the  Sweet  Potato  5 

the  crown  of  the  plant.  Though  these  tubers  are  botan- 
ically  enlarged  roots,  they  are  seldom  spoken  of  as  such 
because  of  the  confusion  that  may  arise  from  the  fact 
that  the  word  "  root "  may  denote  either  the  slender 
fibrous  feed-roots,  the  culls  or  "  seed  potatoes,"  or  th(3 
enlarged  edible  root.  The  word  "  potatoes  "  is  the  uni- 
versal term  in  the  southeastern  states  while  outside  this 
territory  "  sweet  potato  "  is  used  in  contradistinction  to 
the  "  Irish,"  "  round  "  or  "  white  "  potato. 

BOTANICAL   CLASSIFICATION 

The  sweet  potato  belongs  to  the  Convolvulaceae  or 
Morning-Glory  family.  The  Convolvulaceae  is  a  very 
large  and  widely  distributed  family,  making  the  problem 
of  proper  classification  rather  difiicult.  The  sweet 
potato  is  an  Ipomcea,  a  genus  that,  according  to 
House  in  Bailey's  Standard  Cyclopedia  of  Horticulture, 
comprises  "  over  400  species  of  which  more  than  200 
occur  in  Tropical  America,  chiefly  in  Mexico."  Two 
species  are  native  in  the  northeastern  states,  and  others 
are  run  wild.  The  sweet  potato  has  been  accorded  dif- 
ferent designations  in  the  divisions  of  this  rather  com- 
plex family,  by  various  botanists.  Linnaeus  gave  the 
plant  the  name  Convolvuhis  Batatas,  and  Choisy  the 
name  Batatas  edulis,  while  Poiret  put  it  into  the  genus 
Ipomoea,  as  I  Batatas,  the  name  it  now  holds. 

De  Candolle  (Origin  of  Cultivated  Plants)  says  that 
the  word  Batatas  is  American,  coming  from  a  mistaken 
transfer  of  "  potato,"  and  he  mentions  Humboldt  as 
using  the  Mexican  name  of  Camote,  Clusius  the  words 
Batatas,  Camotes,  Amotes,  Ajes,  all  supposed  to  be  of 
American  origin  or  at  least  foreign  to  the  Old  World 
and  none  referring  to  any  of  the  Ipomoeas,     This  writer 


6  The  Sweet  Fotaio 

also  concludes  that  there  is  no  Sanskrit  name  for  the 
plant  and  the  Uengalee  name  of  ruktalu  (which  he  says, 
though  being  derived  from  Sanskrit  has  been  mistaken 
for  a  pure. derivative  of  that  ancient  language),  indicates 
in  modern  langiiages  yam  and  potato.  Attempts  have 
been  made  to  connect  the  word  Batatas  with  oriental 
languages  but  with  indifferent  success.  Although  the 
sweet  potato  appears  to  have  been  known  in  China  as 
early  as  the  second  or  third  century,  this  fact  does  not 
prove  an  eastern  origin.  It  appears  to  have  been  widely 
distributed  by  primitive  Pacific  peoples. 

Probably  it  is  derived,  by  a  long  process  of  do- 
mestication, from  the  tropical  American  Ipomoea  fasti- 
giata.  This  latter  plant  is  described  by  Cook  and 
Collins  (Economic  Plants  of  Porto  Rico)  as  ''  Bejuco 
de  puerco ;  a  twining  vine  found  in  waste  places ;  the 
tuberous  roots  are  called  wild  potatoes  in  Jamaica." 

The  word  yam  is  commonly  applied  to  forms  of  the 
sweet  potato,  although  it  properly  belongs  only  to  species 
of  Dioscorea,  a  very  different  plant.  Various  varieties 
of  s^veet  potato  yams  are  grown  in  India,  Japan,  Sum- 
atra, Java,  Philippines,  and  numerous  Pacific  Islands. 
Some  of  them  have  pyriform  spindles  while  others 
assume  the  form  of  spherical  rhizomes.  Several  species 
are  also  found  in  countries  of  South  America.  The 
word  yam  is  supposed  to  have  originated  in  Africa  and 
in  several  African  dialects  is  said  to  mean,  "  to  eat.'' 
Whether  the  fondness  of  the  southern  negro,  for  "  Yam 
Taters  "  offers  any  clue  to  the  intricacies  of  this  early 
history,  is  not  known.  But  the  word  is  used  with  such 
indefinite  and  variable  meaning  by  people  of  the  United 
States  in  referring  to  the  sweet  potato,  that  it  had  best 


Origin  and  Description  of  the  Sweet  Potato  7 

be  dropped.  It  is  not  only  botanically  incorrect  but 
causes  considerable  confusion  in  markets  which  hinders 
or  prevents    stabilization   of   varietal   trade   demands. 


CHAPTER  II 
IMPORTANCE  AND  DISTRIBUTION 

The  growing  of  the  sweet  potato  has  become  one  of 
the  most  important  food-producing  industries.  The 
extension  of  this  crop  has  been  continually  on  the  in- 
crease for  the  past  several  years  and  it  now  ranks  sec- 
ond only  to  the  Irish  potato  as  a  vegetable  in  the  United 
States.  The  value  of  the  crop  in  1917  reached  the 
hitherto  unparalleled  sum  of  $96,121,000  and  that  of 
1918  was  estimated  at  $116,867,000. 

Although  always  groMTi  to  a  limited  extent  by  prac- 
tically every  farmer  in  the  cotton-belt,  the  sweet  potato 
until  recently  has  been  accorded  a  secondary  place  in 
the  average  southern  rotation.  The  increasing  demand 
for  the  crop  is,  however,  revolutionizing  former  cul- 
tural and  storage  methods  and  with  its  wide  adaptabil- 
ity to  various  climatic  and  soil  conditions,  its  ease  of 
production,  and  with  an  increasing  appreciation  of  its 
value  as  food  resulting  in  its  introduction  into  new  sec- 
tions, within  the  last  few  years  there  has  been  a  rapid 
increase  in  popular  favor  of  the  crop.  Alabama,  pro- 
ducing only  6,290,000  bushels  in  1916,  almost  doubled 
this  yield  in  1918  when  it  produced  14,688,000 
bushels.  (Tables  I  to  V.)  With  the  exception  of 
certain  western  sections,  a  similar  though  perhaps  less 
increased  interest  in  production  has  been  experienced 
over  almost  the  entire  sweet  potato  area.  (Tables  I 
toV.) 


Importance  and  Distribution 


Table  I. —  Sweet  Potatoes  :  Estimates  of  Acreage,  Yield 
PER  Acre,  Total  Production,  Price  to  the  Bushel,  Total 
Farm  Value  and  Value  to  the  Acre  by  States  in  1918. 


State 

Acreage 

(000 
omitted) 

Yield 
per 
Acre 

Produc- 
tion 
(000 

omitted) 

Price 
per  Bu. 
Dec.  1 

Total 

Value 

(000 

omitted) 

Value 
Acre 

New   Jersey .... 
Pennsylvania   . . 

Delaware     

Maryland    

Virginia    

West    Virginia.. 
North    Carolina. 
South  Carolina. 

Georgia    

Florida    

Ohio    

Indiana    

Illinois    

Iowa    

Missouri    

Kansas    

Kentucky    

Tennessee    

Alabama    

Mississippi    .... 

Louisiana    

Texas    

23 
1 
5 

11 

28 

2 
81 
80 
130 
36 

1 
3 
8 
3 
8 

4 

13 

30 

153 

89 

65 
87 
15 
38 
2 

6 

125 
120 
120 
130 
120 

106 

110 

95 

92 

110 

96 
108 
82 
93 
91 

80 
95 
98 
96 
95 

75 

58 
65 
90 
125 
170 

2,875 

120 

6Q0 

1,430 

3,360 

212 
8,910 
7,600 
11,960 
3,960 

96 
324 
656 

279 

728 

320 
1,235 

2,940 
14,088 
8,455 

4,875 
5,046 

975 
3,420 

250 
1,020 

190 
185 
125 
150 
145 

204 
132 
142 
125 
125 

175 
195 
175 
210 
186 

222 
175 
136 
115 
104 

128 
175 
220 
138 
250 
150 

5,462 
222 
750 

2,145 

4,872 

432 
11,761 
10,792 
14,950 
4,950 

168 
,632 

1,148 
586 

1,354 

710 
2,161 
3,998 
16,891 
8,793 

6,240 
8,830 
2,145 
4,720 
625 
1,530 

237.50 
222.00 
150.00 
195.00 
174.00 

216.24 
145.20 
134.90 
115.00 
137.50 

168.00 
210.60 
143.50 
195.30 
169.26 

177.60 
166.25 
133.28 
110.40 

98.80 

96.00 
101.50 

Oklahoma    

Arkansas    

New    Mexico. .  .  . 
California    

143.00 
124.20 
312.50 
255.00 

United    States.. 

922 

93.6 

86,334 

135.4 

116,867 

126.75 

The  farm  value  of  sweet  potatoes,  which  has  more 
than  doubled  in  the  past  ten  years,  has  increased  more 
rapidly  than  acreage  or  production.  This  tuber  is 
now  one  of  the  principal  vegetable  foods  of  the  southern 
states,  and  its  use  can  be  enormously  increased  in  all 


10 


The  Sweet  Potato 


sections  of  the  United  States,  especially  in  the  northern 
and  western  areas. 


DISTRIBUTION 

Although  the  sweet  potato  is  gro\\Ti  as  a  garden  crop 
as  far  north  as  scmthern  New  York,  northern  Illinois, 
central  Iowa  and  Nebraska,  its  commercial  production, 
is  confined  very  largely  to  the  South  Atlantic  and  Gulf 
Coast  states.  A  fair  commercial  crop  is  produced  west- 
ward along  the  border  line  between  the  United  States 
and  Mexico  extending  into  central  California.      (Fig. 

1-) 

The  commercial  crop  is  raised  mainly  in  eighteen 
states:  the  Southeastern  group,  comprising  Virginia, 
North  and  South  Carolina,  Georgia,  Florida,  Alabama, 
Louisiana  and  Mississippi.     Sweet  potatoes  are  grown 


Figure  1. —  Map  showing  range  of  production  of  sweet  potatoes. 
The  shaded  portion  represents  the  area  adapted  to  commercial 
growing.  The  dark  line  represents  the  northern  limits  of  sweet 
potato  culture  for  home  use. 


Importance  and  Distribution 


11 


quite  extensively  in  Texas,  Oklahoma,  Tennessee,  Ar- 
kansas and  California,  while  the  northern  crop  which 
figures  very  largely  in  car-lot  shipments,  is  produced 
chiefly  in  jS'ew  Jersey,  Delaware,  Maryland,  Illinois  and 
Iowa.  Production  has  increased  rapidly  in  some  states, 
having  nearly  doubled  between  1915  and  1918  in  Ala- 
bama which  gives  it  the  leading  place  among  the 
sweet  potato  growing  states,  while  Georgia  with  an 
increase  nearly  as  rapid  takes  second  place  in  produc- 
tion. Northern  and  western  producing  sections  as  a 
whole  show  many  decreases  during  recent  years.  How- 
ever, a  few  small  localities  in  these  areas  have  developed 
a  considerable  industry  by  the  use  of  large  curing- 
houses  and  it  is  very  probable  that  these  sections  will 
rapidly  increase  their  acreage  and  yields  within  the  next 
few  years.  Tables  TI,  III  and  IV  give  in  complete 
form  the  geographic  distribution  and  the  economic  value 
of  the  sweet  potato  in  the  various  sections  of  the  United 
States  since  1899. 


Table  II. —  Production  and  Value  op  Sweet  Potatoes  and 
Yams  in  the  United  States,  by  Divisions  and  States 
IN  1899  and  1909,  as  Eeported  by  the  Twelfth  and 
Thirteenth  United  States  Censuses. 


Division    or    State. 

Production. 

Value. 

1909. 

1899. 

1909. 

1899. 

Geographic 
Divisions: 

Bushels. 

Bushels. 

Dollars. 

Dollars. 

New    Eiifrland 

Middle    Atlantic... 
East  North   Central 
West  North  Central 

South    Atlantic 

East   South   Central 
West  South  Central 

4.818 
3,326.190 
1.364,2.i6 
1,696,111 
29.628.153 
13,573,580 
9,025,928 

567 
2,662,046 
1,004,277 
1,491,275 
21,881,977 
8,772,133 
6,439,547 

4,543 
1,638,902 
751,929 
1.095,724 
16,146,222 
9,116,510 
6,265,750 

346 
1,349,588 
619,833 
805,669 
9,183,650 
4,536.187 
3,220,595 

13 


The  Sweet  Potato 


Division  or  State. 

Production. 

Value. 

1909. 

1899. 

1909. 

1899. 

Geoj^raphic 
Divisions: 

Bushels. 

Bushels. 

Dollars. 

Dollars. 

Mountain   ... 

38,877 
574,157 

19,064 
246,526 

52,596 
357,000 

14,207 
139,765 

Pacific    

Principal  States. 

Middle  Atlantic: 

New    Jersey 

3,186,499 

2,418,641 

1,527,074 

1,213,010 

Pennsylvania    .  .  . 

128,770 

234,724 

104,434 

130,990 

East  North  Central 

Ohio    

133,798 

249,767 

104,181 
139,886 

158,103 
155,585 

Indiana    

178,300 

239,487 

Illinois 

1,050,932 

511,695 

506,760 

303,638 

West  North  Central : 

Iowa    

232,413 

224,622 

125,763 

128,981 
424,470 

Missouri     

876,2.34 

743,377 

567,413 

558,021 

474,810 

373,432 

224,049 

South  Atlantic: 

Delaware    

733,746 

222,165 

276,679 

96,566 

Maryland    

1,065,956 

677,848 

483,751 

317,462 

Virginia   

5,270,202 

4,470,602 

2,681,472 

1,720,188 

West   Virginia.  .  . 

215,582 

202,424 

170,086 

125,523 

North    Carolina.. 

8,493,283 

5,781,587 

4,333,297 

2,119,956 

South    Carolina.  . 

4,319,926 

3,369,957 

2,606,606 

1,538,205 

Georgia    

7,426,131 

5,087,674 

4,349,806 

2,354,390 

Florida     

2,083,665 

2,049,784 

1,231,238 

898,282 

East  South  Central : 

Kentucky     

1,-326,245 

925,786 

839,4.54 

507,038 

Tennessee     

2,-504,490 

1,571,575 

1,625,056 

883,620 

Alabama     

5,314,857 

3,457,386 

3,578,710 

1,687,039 

Mississippi    

4,427,988 

2,817,386 

3,073,290 

1,458,490 

West  South  Central: 

Arkansas    

1,685,308 

998,767 

1,359,669 

534,616 

Louisiana     

4,251,086 

1,805,482 

2,357,729 

859,733 

Oklahoma    

3-59,451 

a  276,163 

350,-553 

a  137,231 

Texas    

2,730,083 

3,299,135 

2,197,799 

1,689,015 

Pacific : 

California    

-572.814 

239.029 

355,624 

135,612 

All    others 

106,290 

107,539 

109,414 

68,048 

United  States.. 

59,2.32.070 

42,517,412 

35,429,176 

10,S69,840 

a  Includes  Indian  Territory. 


Importance  and  Distribution 


13 


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Importance  and  Distribution 


15 


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16  The  Sweet  Potato 

CLIMATIC    EEQUIKEMENTS    AND    SOIL    TYPES 

A  liberal  rainfall,  with  warm  nights  and  abundant 
sunshine,  lasting  throughout  the  growing  season,  with 
less  moisture  during  the  two  months  preceding  matur- 
ity, constitute  ideal  weather  conditions  for  sweet  pota- 
toes. A  gi-owing  period  of  at  least  130  days  is  essential 
for  the  production  of  maximum  yields. 

While  requiring  a  heavy  rainfall  during  the  late 
spring  and  summer  to  insure  vigorously  growing  plants 
and  the  formation  of  an  abundant  and  well-shaped 
tuber  crop,  considerably  less  rain  is  needed  as  the  time 
of  harvest  approaches.  In  fact,  much  rain  at  this  time 
may  result  in  a  considerable  loss  to  the  grower  by  injur- 
ing the  flavor  of  the  potato  and  greatly  impairing  its 
keeping  and  shipping  quality.  An  unusually  long  con- 
tinued spell  of  wet  weather  in  the  fall  has  often  resulted 
in  great  loss  to  growers  along  the  Atlantic  and  Gulf 
coasts,  sometimes  causing  the  entire  crop  to  rot  in  the 
field  and  more  often  causing  a  souring  of  the  potato 
which  makes  it  easily  susceptible  to  disease  attack  on 
the  slightest  bruising,  and  rendering  it  practically  im- 
possible of  successful  storage.  This  condition  occurred 
throughout  all  the  counties  bordering  the  Gulf  of  Mexico 
in  the  fall  of  1918  and  in  the  same  year  the  crop  was 
more  or  less  injured  all  along  the  Atlantic  coast.  (The 
handling  of  the  crop  under  these  conditions  is  fully 
treated  under  Chapter  X.)  It  is  also  believed  by 
some  growers  that  heavy  late  rains  increase  the  tendoncy 
to  cracking  or  splitting  in  the  tubers,  although  the  scien- 
tific reason  for  this  common  occurrence  has  not  yet  been 
satisfactorily  determined.  Such  late  rains  following  a 
dry  season,  though  not  excessive,  tend  to  create  a  re- 


Importance  and  Distribution  17 

newal  or  second  growth  of  the  tubers  which  causes  ex- 
cess sappiness  and  makes  handling  in  transit  more 
difficult.  On  the  other  hand,  severe  drouths  late  in  the 
season  make  harvesting  tedious. 

Where  irrigation  must  be  practiced,  as  will  be  nec- 
essary in  some  parts  of  Texas,  New  Mexico  and  Ari- 
zona, most  of  the  water  should  be  applied  between  the 
time  the  plants  are  set  and  the  ground  becomes  covered 
with  vines.  The  water  is  withheld  altogether  for  several 
Avceks  preceding  harvest,  to  permit  the  proper  ripening 
of  the  tubers. 

A  climate  with  an  abundance  of  sunshine  and  warm 
nights  is  necessary  for  thrift.  A  temperature  ranging 
from  70  to  100  degrees  F.  during  the  summer  growing 
period  is  a  good  average  for  maximum  yield,  although 
in  a  small  way  *'  sweets  "  may  be  produced  under  a 
wide  range  of  temperatures  as  well  as  soil  types.  ISTorth 
of  the  cotton-belt,  the  sweet  potato  is  commonly  re- 
garded as  a  garden  crop. 

The  sweet  potato  crop  is  exceedingly  sensitive  to  frost 
and  growth  is  noticeably  checked  by  cool  weather. 
Growers  in  the  southern  Gulf  states  have  found  it 
profitable  to  set  their  plants  in  the  field  a  little  later 
in  the  spring  rather  than  have  them  stunted  by  the 
cool  nights.  The  sweet  potato  is  strictly  a  summer  crop 
and  grows  best  in  the  hottest  part  of  the  year. 

It  requires  about  four  and  one-half  months  for  the 
sweet  potato  to  reach  normal  maturity.  A  potato  that 
is  immature  is  harder  to  keep  in  storage  and  shrinks 
more  than  one  fully  mature.  The  amount  of  starch, 
sugar  and  other  constituents  as  well  as  their  form  and 
availability  differ  materially  at  various  periods  of 
growth.     The  relative  length  of  the  growing  period  is 


18  The  Sweet  Potato 

the  limiting  factor  of  production  as  the  line  indicative 
of  profitable  growth  is  moved  northward. 

The  sweet  potato  finds  its  most  desirable  soil  en- 
vironment when  planted  on  light  friable  loam  or  sandy 
soil  with  a  yellow  clay  subsoil.  A  well-drained  soil 
that  is  warm  and  loose  with  a  gftod  proportion  of  sand 
in  the  top  soil  and  a  subsoil  fairly  retentive  of  moisture 
provides  ideal  conditions.  A  moderately  fertile  sandy 
loam  lacking  an  excess  of  undecayed  organic  matter  is 
preferable,  although  a  fairly  good  yield  can  often  be 
obtained  on  soils  too  poor  for  the  production  of  most 
farm  crops.  Large  yields  of  the  most  desirable  market 
type  of  potatoes  are  sometimes  produced  on  some  of  the 
driest  and  most  sandy  soils  when  the  growing  condi- 
tions are  favorable,  but  care  in  the  selection  of  suitable 
areas  usually  pays  in  greatly  increased  returns.  The 
depleted  cotton  and  tobacco  lands  of  the  South  can  be 
made  to  give  excellent  returns  in  sweet  potatoes  when 
intelligent  care  is  exercised  to  provide  a  supply  of 
humus  in  the  soil  by  a  leguminous  crop  in  the  rotation. 
The  loams  and  mixed  sandy  soils  of  northern  Louisi- 
ana, the  friable  chocolate  loams  of  northeast  Texas,  the 
cut-over  long-leaf  yellow  pine  lands  of  Mississippi, 
Alabama,  Georgia,  and  Florida,  northern  and  eastern 
South  Carolina,  the  lower  sand  hills  and  coastal  regions 
of  North  Carolina,  eastern  Virginia,  lower  New  Jersey 
and  Delaware,  the  sandy  localities  of  the  Kaw  and 
Arkansas  valleys  in  Arkansas  and  eastern  and  southern 
Tennessee,  all  afford  soil  types  well  suited  to  the  com- 
mercial production  of  this  important  food  crop.  Other 
sections  of  these  same  states,  as  the  Piedmont  regions 
of  northern  Georgia  and  North  Carolina,  supply  soil 
conditions   possible  of  profitable   development  but  re- 


Importance  and  Distribution  19 

quiring  different  treatment  and  handling.  The  custom, 
of  planting  on  high  ridges  is  for  the  purpose  of  facili- 
tating drainage.  A  porous  clay  subsoil  not  only  sup- 
plies drainage  without  the  leaching  of  plant-food  but 
it  is  an  important  factor  in  the  production  of  well- 
shaped  tubers.  A  very  deep  sandy  soil  without  a  sub- 
stantial foundation  permits  the  loss  of  valuable  fer- 
tilizing elements  by  leaching  and  often  produces  long 
ill-shaped  potatoes  that  do  not  bring  the  highest  prices 
on  discriminating  markets.  The  surface  soil  should  be 
six  or  eight  inches  deep  and  the  subsoil  should  provide 
drainage  without  leaching.  A  stiff  soil  favors  excessive 
vine  growth  and  the  production  of  rough  irregular  po- 
tatoes. Such  soils  also  are  usually  cold  and  in  the  end 
will  prove  unprofitable  for  commercial  plantings.  The 
sweet  potato  is  possible  of  profitable  growth  on  a  wider 
range  of  soil  than  perhaps  any  other  of  the  common 
field  crops. 


CHAPTER  III 


UTILIZATION  OF  THE  SWEET  POTATO 


The  most  important  use  of  the  sweet  potato  is  as 
a  food  for  man,  either  in  its  original  form  or  as  manu- 
factured into  a  flour  or  starch.  It  may  also  have  an 
important  place  in  the  rations  for  live-stock. 

T.  E.  Keitt  ^  of  South  Carolina  gives  the  chemical 
analysis  of  the  sweet  potato  vine  (average  of  four 
varieties)  and  tubers  (average  fourteen  varieties)  re- 
spectively to  be : 

Table  VI. —  Analysis  of  Sweet  Potato  Tubers  and  Vines. 


Dry 
Matter 

Protein 

Nitro- 

Pfe^ 
Extract 

Fat 

Fiber 

Ash 

Water 

Sweet    Potato 
Tubers.... 

39.1 

1.6 

27.9 

0.5 

0.9 

1.0 

C8.1 

Sweet     Potato 
Vines  — 
Fresh    

'     17.0 

2.1 

9.5 

0.8 

3.1 

1.5 

83.0 

Attention  is  called  to  the  fact  that  the  nitrogen-con- 
tent of  the  sweet  potato  occurs  in  the  readily  avaihible 
form  of  albuminoids  which  render  this  food  element 
capable  of  full  utilization  in  digestion  processes.  This 
is  an  important  item  to  be  considered  in  calculating  the 
comparative  food  value  of  this  crop  with  that  of  some 
other  crops  which,  although  containing  a  higher  percent- 

1  Bull.  146,  S.  C.  Exp.  Sta.,  1908. 
20 


utilization  of  the  Sweet  Potato  21 

age  of  nitrogenous  substances,  are  not  worth  so  much  in 
actual  feeding  value  because  of  the  unavailable  form  in 
which  they  occur. 

AS    FOOD    FOR    MAN 

As  a  food  for  human  consumption,  the  sweet  potato 
has  always  been  held  in  very  high  esteem  by  the  peoples 
of  the  southern  United  States,  South  America,  parts  of 
Asia  and  many  of  the  tropical  islands.  In  the  Philip- 
pines and  Hawaiian  Islands,  it  furnishes  one  of  the 
main  sources  of  food  supply,  notwithstanding  the  fact 
that  there  is  no  trade  in  the  crop  aside  from  purely  local 
markets. 

The  sweet  potato  is  highly  nutritious  and  contrary 
to  the  common  belief  is  easily  digested.  If  ingenuity  is 
employed  in  its  utilization,  many  palatable  ways  of 
serving  it  are  available,  such  as  baked,  boiled,  served 
with  meats,  in  soups,  candied,  in  salads,  desserts,  and 
even  for  the  production  of  sirup  and  as  a  flour  substi- 
tute. Its  use  is  also  developing  in  making  desserts, 
cereals,  cakes  and  various  drinks. 

Composition  and  food  value. 

Although  the  sweet  potato  differs  botanically  from 
the  Irish  potato,  in  general  chemical  composition  the 
root  resembles  very  closely  the  tubers  of  the  white  po- 
tato. There  are,  however,  some  important  differences 
as  shown  in  Table  VII. 

It  will  be  noted  that  the  sweet  potato  as  purchased 
has  a  fuel  value  in  calories  equal  to  approximately  one- 
half  more  than  does  the  white  potato.  The  water  con- 
tained is  less  than  that  of  the  white  potato  and  although 


22 


The  Sweet  Fotato 


Table  VII. —  Composition  of  the  Sweet  Potato  and  Irish 
Potato  Coaipaueu. 


Kind 

OF 

Potato 

Refuse 
Per 
cent. 

Water 
Per 
cent. 

Pro- 
tein 
Per 
cent. 

Fat 
Per 
cent. 

Carbohydrates 

Ash 

Food 

Values 

Sugar, 

aturch, 

etc. 

Crude 
Fiber 

Per 
Pound 

Calories 

Sweet  potato 
(edible 
poilion). 

69.0 

1.8 

0.7 

26.1 

1.3 

1.1 

560 

Sweet  potato 
(as    pur- 
chased)  .  . 

20.0 

55.2 

1.4 

0.6 

21.9 

.9 

450 

Sweet  potato 
(cooked) 

51.9 

3.0 

2.1 

42.1 

.9 

905 

Sweet  potato 
(canned) 

55.2 

1.9 

.4 

40.6 

.8 

1.1 

800 

White     pota- 
to —  for 
compari- 
son (edible 
portion). 

78.3 

2.2 

.1 

18.0 

.4 

1.0 

375 

White     pota- 
to —  for 
compari- 
son   (as 
purchased) 

20.0 

62.6 

1.8 

.1 

14.7 

.8 

305 

the  percentajje  of  crude  fiber  is  slightly  higher,  it  is 
about  that  commonly  found  in  most  vegetables  (see 
Table  VIII).  Although  it  would  seem  that  the  white 
potato  is  slightly  higher  in  protein,  actually  the  sweet 
potato  contains  more  available  protein.  This  is  ex- 
plained by  the  fact  that  a  large  part  of  the  protein  in 
the  white  potato  occurs  in  the  form  of  amides  which  are 
not  available  as  food.  The  sweet  potato  is  consider- 
ably richer  in  fat  and  contains  a  perceptibly  greater  per- 
centage of  available  carbohydrates  than  does  the  white 
potato.  The  ash-content  is  approximately  the  same  and 
about  the  same  waste  occurs  in  peeling.     As  indicated 


utilization  of  the  Sweet  Potato  23 

bj  the  table,  sweet  potatoes  contain  considerable  quan- 
tities of  sugar.  This  sugar-content  is  influenced  to  a 
marked  degree  by  the  climatic  conditions  under  which 
the  roots  are  grown,  tropical  varieties  often  containing 
as  much  sugar  as  starch,  while  those  grown  in  the 
northern  areas  of  the  United  States  often  average  less 
than  7  per  cent  sugar,  or  less  than  one-fourth  of  their 
total  carbohydrates. 

Few  crops  will  yield  an  equal  amount  of  valuable 
food  stuff  with  as  little  expense  of  production.  The 
sweet  potato  is  especially  rich  in  nitrogen  free  extract 
which  consists  primarily  of  sugar  and  starch.  Both  of 
these  food  elements  are  producers  of  heat  and  energy. 
Fats  and  carbohydrates,  containing  carbon  as  the  essen- 
tial element,  are  only  valuable  for  fuel.  On  the  other 
hand,  protein,  containing  nitrogen,  is  the  essential  ele- 
ment in  tissue  building  and  is  necessary  in  any  balanced 
ration  whether  for  man  or  other  animal.  Lean  meat, 
the  white  of  egg,  milk,  beans  and  peas  furnish  the  most 
familiar  examples  of  foods  high  in  protein.  Sweet  po 
tatoes  in  any  ration  must  be  supplemented  by  such 
foods.  About  10  per  cent  of  the  total  number  of  heat 
units  consumed  in  any  human  ration  should  be  protein. 
This  does  not  mean  10  per  cent  of  the  total  weight  or 
bulk  but  10  per  cent  of  the  total  nutriment.  In  other 
words,  out  of  every  100  calories  of  food  consumed  only 
ten  calories  of  protein  are  needed.  A  diet  containing  10 
per  cent  protein,  30  per  cent  fats  and  60  per  cent 
carbohydrates  is  a  well  balanced  one.  In  the  prepara- 
tion of  a  palatable  wholesome  and  well  balanced  meal, 
the  housewife  will  find  no  more  economical  and  satis- 
factory source  of  carbohydrates  than  in  the  sweet  po- 


24  The  Sweet  Potato 

tato;  pound  for  pound  the  sweet  potato  contains  about 
one-half  more  available  food  than  does  the  more  com- 
monly used  Irish  potato. 

Aside  from  the  purely  chemical  food  value  of  the 
sweet  potato,  it  supplies  valuable  mineral  salts  which 
are  not  obtained  in  cereal  carbohydrates.  These  min- 
eral salts,  which  are  composed  largely  of  potassium 
compounds,  are  very  valuable  in  offsetting  the  acid 
effect  brought  about  by  meats  and  other  common  pro- 
tein foods  in  the  body.  To  maintain  the  system  in  a- 
state  of  vigor  and  efficiency,  the  general  diet  should  be 
neutral  or  slightly  alkaline  rather  than  overly  acid. 
ISTothing  is  so  valuable  as  an  alkaline  medicine  as  fresh 
vegetables  and  in  supplying  these  mineral  salts  the  sweet 
potato,  because  of  its  many  ways  of  preparation  and 
palatability,  will  be  found  to  rank  well  in  the  list  of 
cheaply  available  vegetables.  The  sweet  potato  is  easily 
prepared  and  has  the  goods  points  of  a  cereal  plus  the 
advantages  of  a  vegetable.  Although  containing  less 
fat  and  protein  than  most  cereals,  it  furnishes  the  body 
a  large  proportion  of  mineral  substances.  A  cupful  of 
boiled  potatoes  would  furnish  the  body  with  about  as 
much  energ}^  as  a  cupful  of  boiled  rice.  Although  the 
available  protein  in  the  sweet  potato  may  be  a  little 
more  easily  digested  than  that  of  the  Irish  potato,  yet 
the  difference  is  so  small  as  to  be  negligible.  All  experi- 
mental data  available  indicates  a  degree  of  digestibility 
equal  to  that  of  white  potatoes.^  C.  F.  Langworthy 
says,  "  It  is  a  matter  of  common  experience  that  sweet 
potatoes  are  wholesome,  and  they  are  ordinarily  di- 
gested without  distress.     Many  persons  find  the  starchy 

1  Bull.  468,  U.  S.  Dept.  Agr.,  page- 21. 


Utilization  of  the  Siveet  Potato  25 

varieties  so  dry  that  they  do  not  relish  them  without 
large  quantities  of  butter.  This  makes  a  rather  rich 
mixture  and  is  perhaps  accountable  for  the  digestive 
disturbances  occasionally  experienced.  Considering 
both  composition  and  digestibility,  it  may  be  said  that 
the  nutritive  value  of  sweet  potatoes  is  much  the  same  as 
that  of  white  potatoes  and  that  they  are  well  fitted  to 
occupy  the  same  place  in  the  diet  and  furnish  a  palatable 
substitute  for  white  potatoes.  The  characteristic  and 
pleasing  flavor  has  the  advantage  of  giving  variety  to 
the  diet.  In  the  North  they  frequently  cost  somewhat 
more  than  white  potatoes,  but  are  still  among  the 
cheaper  vegetables.  In  the  South  they  are  usually 
cheaper  than  white  potatoes  and  merit  their  extensive 


AS  rOOD  FOR  DOMESTIC  ANIMALS 

In  consideration  of  the  great  need  with  which  this 
country  is  confronted,  and  especially  the  South,  for  a 
cheaper  and  more  easily  produced  carbohydrate  than 
corn,  sweet  potatoes  might  well  be  considered  as  a 
source  of  this  food  element  for  all  domestic  animals. 
Owing  to  the  ease  with  which  it  is  produced,  the  ex- 
ceptional food  value  and  the  readiness  with  which  it  is 
consumed  by  practically  all  domesticated  animals,  it  is 
natural  to  expect  that  the  sweet  potato  will  play  a  more 
important  part  in  food  rations  as  its  general  produc- 
tion is  increased.  Heretofore,  when  the  consumption 
of  this  crop  has  been  limited  to  a  few  weeks  in  the  fall 
when  the  hogs  were  turned  on  the  fields  to  dig  up  the 
roots  left  by  oversight,  little  attention  was  paid  to 
feeding  it  and  little  was  thought  of  its  feeding  value. 
With  the  advent  of  improved  storage  houses  from  which 


26  The  Sweet  Potato 

the  tubers  can  be  taken  at  any  season  of  the  year  as 
conveniently  as  corn  from  the  crib,  farmers  are  rap- 
idly giving  more  attention  to  the  possibilities  of  the  crop 
as  a  source  of  nutritious,  succulent  and  palatable  food- 
stuff for  their  live-stock.  At  present  sweet  potatoes 
cured  in  the  storage-house  bring  midwinter  prices,  which 
makes  them  prohibitive  for  feeding  purposes  when  con- 
venient transportation  facilities  are  available.  How- 
ever, many  farmers  live  too  far  from  the  railroad  to 
make  hauling  to  market  of  such  a  bulky  crop  profitable 
and  they  will  always  find  it  a  good  policy  to  preserve 
the  crop  for  feeding  purposes.  The  very  interesting 
results  recently  obtained  by  the  Florida  Experiment 
Station  with  the  feeding  of  sweet  potato  silage  to  dairy 
cattle  opens  up  a  new  field  in  the  feeding  of  the  crop. 
Feeding  to  live-stock  will  always  be  a  profitable  way 
of  marketing  the  culls,  the  bruised  and  ill-shaped  crop. 
All  kinds  of  stock  relish  them  and  because  of  the  high 
content  of  dry  matter,  they  possess  a  decided  advantage 
over  the  other  root-crops.  They  can  be  depended  on 
to  contain  an  average  of  10  per  cent  more  dry  matter 
than  the  Irish  potato,  and  more  than  20  per  cent  more 
than  common  beets,  mangels,  turnips,  rutabagas,  car- 
rots or  parsnips.  (Table  VIII.)  The  yield  in  many 
sections  is  larger  than  that  of  the  Irish  potato  and  the 
"  sweets  "  are  not  so  subject  to  disease  and  insect  en- 
emies in  the  field,  nor  are  they  so  expensive  to  fertilize, 
propagate  and  cultivate.  The  following  table  ^  gives 
the  average  feeding  stuff  analysis  of  several  similar 
crops  and  also  that  of  corn : 

1  Bull.  146,  S.  C.  Exp.  Sta. 


utilization  of  the  Sweet  Potato 


27 


Table  VIII. 


Irish  potato.  .  .  . 
Beets,  common.  . 
Beets,  mangels.  . 
Beets,   sugar .... 

Turnips    

Rutabagas    

Carrots   

Parsnips     

Artichoke     

Sweet  potato.  .  . 
Corn    


Showing  Analysis  of  Various  Feedikg 
Stuffs.^ 


Per 
cent. 
Water 

Per 
cent. 
Ash 

Per 

cent. 

Protein 

Per 

cent. 

C.  Fiber 

Per 

cent. 

N.  Free 

Extract 

78.9 

1.0 

2.1 

0.6 

17.3 

88.5 

1.0 

1.5 

0.9 

8.0 

90.9 

1.1 

1.4 

0.9 

5.5 

86.5 

0.9 

1.8 

0.9 

9.8 

90.5 

0.8 

1.1 

1.2 

6.2 

88.6 

1.2 

1.2 

1.3 

7.5 

88.6 

1.0 

1.1 

1.3 

7.6 

88.3 

0.7 

1.6 

1.0 

10.2 

79.5 

1.0 

2.6 

0.8 

15.9 

68.1 

1.0 

1.6 

0.9 

27.9 

10.6 

1.5 

10.3 

2.2 

70.4 

Per 

cent. 

Ether 

Extract 

0.1 
0.1 
0.2 
0.1 
0.2 
0.2 
0.4 
0.2 
0.2 
0.5 
5.0 


Keitt  says  concerning  the  analysis  of  the  above  crops : 
"  On  land  in  this  State  (meaning  South  Carolina) 
which  under  the  ordinary  system  of  cropping,  yield  20 
bushels  of  corn,  we  should  be  able  to  produce  about  200 
bushels  of  sweet  potatoes.  The  potatoes  would  furnish 
more  than  three  times  as  much  nitrogen  free  extract 
and  as  much  or  more  of  each  of  the  other  proximate 
constituents  contained  in  the  corn.  From  the  preced- 
ing table,  we  will  note  that  the  Irish  potato  contains 
2.1  per  cent,  of  protein,  which  is  more  than  the  amount 
contained  in  the  sweet  potato;  but  about  one-half  of  the 
calculated  protein  of  the  Irish  potato  is  really  nitrogen 
present  in  the  form  of  amides,  which  do  not  have  the 
feeding  value  that  the  albuminoids  have.  In  order  to 
determine  whether  or  not  any  of  the  nitrogen  present 
in  the  sweet  potato  was  present  in  the  form  of  amides, 

1  All  of  the  analyses  were  taken  from  Henry's  "  Feeds  and  Feed- 
ing "  except  that  of  the  sweet  potatoes,  which  represent  the  aver- 
age analysis  of  fourteen  varieties  by  T.  E.  Keitt,  chemist  of  the 
S.  C.  Exjp.  Sta. 


28  The  Sweet  Potato 

we  made  determinations  on  all  of  the  varieties  and 
found  that  there  were  no  amides  present." 

Importance  in  the  proper  balancing  of  the  farm  ani- 
mal's ration  cannot  be  over-emphasized.  The  proper 
proportion  of  heat  and  eneray  producing  foods  with 
muscle  builders  must  be  fed  for  economy  as  well  as  for 
the  well-being  of  the  animal.  It  is  too  often  neglected 
to  give  a  sufficient  amount  of  fat  and  carbohydrates  with- 
the  protein  feed.  Although  protein  when  supplied  in 
over-abundance  will  partly  do  the  work  of  carbohydrates, 
it  is  an  expensive  means  of  supplying  it.  One  part  of 
protein  in  the  food  should  be  supplemented  with  six 
parts  of  fats  and  carbohydrates  for  a  milk  cow.  When 
much  more  protein  than  this  is  used,  it  cannot  be 
assimilated  by  the  animal  and  so  is  lost  in  the  manure. 
As  Keitt  points  out,  a  mixture  of  8  pounds  of  sweet 
potatoes  to  1  pound  of  cotton-seed  meal  would  give  a 
nutritive  ratio  of  approximately  six  to  one.  Such  a 
ration  if  periodically  supplanted  by  other  rations  to 
avoid  getting  the  animal  "  off-feed "  will  give  good 
results.  The  value  of  this  crop  in  the  production  of 
milk  has  been  aptly  illustrated  in  recent  tests  with  the 
ensilage. 

Sweet  potato  silage. 

The  first  record  of  making  the  crop  into  silage  was 
in  1912  when  the  Florida  Experiment  Station  con- 
ducted feeding  experiments  with  sweet  potatoes.  The 
roots  were  run  through  the  ensilage  cutter  and  handled 
the  same  as  any  other  crop.  The  comparative  analysis 
of  corn  and  sweet  potato  silage  was  as  follows : 


utilization  of  the  Sweet  Potato 


29 


Table  IX.— 

Showing  Comparative  Analysis 
Sweet  Potato  Silage. 

OF  Corn  and 

Crop 

Water 

Cnide 
Protein 

Nitrogen 
P.  Extract 

Fiber 

Fat 

Ash 

Sweet  potato 
silage    

Well  matured 
corn   silage 

54.87 
73.7 

1.82 
2.1 

39.41 
15.4 

1.48 
6.3 

.66 

.80 

1.85 
1.7 

Attention  is  called  to  the  fact  that  there  is  very 
little  difference  in  apparent  feeding  value.  There  is, 
however,  about  two  and  one-half  times  as  much  nitro- 
gen free  extract  and  considerably  more  dry  matter  in 
the  potato  silage;  and  experience  showed  the  potato 
silage  to  be  from  50  to  100  per  cent  more  valuable. 

In  a  test  lasting  forty-three  days,  divided  into  twenty- 
day  periods  with  three  days  between  periods  for  the 
purpose  of  changing  feeds,  the  following  results  were 
secured  ^ :  "  Ten  cows  were  used  in  the  test  and  were 
divided  into  two  lots  of  five  cows  each.  During  the 
first  period  each  animal  in  lot  one  was  given  the  follow- 
ing daily  ration;  wheat  bran  8.4  pounds,  cotton-seed 
meal  2.8,  and  sweet  potato  silage  10,6  pounds.  Each 
animal  in  lot  two  v^as  given  the  following  daily  ration : 
Wheat  bran  8.4  pounds,  cotton-seed  meal  2.8,  and 
sorghum  silage  15.2  pounds. 

"  During  the  second  period  feeds  were  reversed,  that 
is,  the  cows  in  lot  one  were  given  the  feed  that  lot 
two  had  received  and  those  in  lot  two  were  given  the 
feed  that  lot  one  had  received. 

"  During  the  experiment  the  cows  fed  sweet  potato 
silage,  wheat  bran  and  cotton-seed  meal  produced  2641 
pounds  or   307.1   gallons  of  milk.     During  the   same 

1  Jno.  M.  Scott,  Press  Bull.  274,  Fla.  Exp.  Sta. 


30  The  Sweet  Potato 

length  of  time  the  cows  fed  sorghum  silage,  wheat  bran 
and  cotton-seed  meal  produced  2415.8  pounds  or  280.9 
gallons  of  milk,  a  difference  of  225.2  pounds  or  26.2 
gallons  of  milk  in  favor  of  sweet  potato  silage. 

''  One  noticeable  fact  in  this  experiment  is  that  the 
cows  ate  one-third  less  sweet  potato  silage  than  sorghum 
silage.  This  is  quite  a  saving  in  the  amount  of  feed 
consumed  by  a  herd  during  the  year." 

Scott  of  the  Florida  Station  is  very  enthusiastic  over 
the  silo  as  a  means  of  preserving  the  crop  for  the  dairy 
cow.  He  gives  the  advantages  of  preserving  as ;  "  No 
loss  in  storage ;  they  require  less  space  for  storage ; 
and  there  is  no  waste  in  feeding."  It  is  possible  that 
this  form  of  silage  will  come  into  more  general  use 
throughout  the  South  when  more  is  known  of  its  feeding 
values. 

Roots. 

The  roots  without  any  special  preparation  are  grown 
extensively  throughout  the  South  for  feeding  purposes, 
especially  for  hogs.  The  Tuskegee  Experiment  Sta- 
tion of  Alabama  found  that  hogs  put  on  almost  as 
much  fat  with  sweet  potatoes  alone  as  with  wheat  shorts 
alone.  ^  This  station  also  found  that  a  grain  ration  of 
corn  could  very  economically  be  cut  in  half  by  sub- 
stituting from  2%  to  3V2  pounds  of  potatoes  for  l^A 
pounds  of  corn  in  feeding  mules  doing  heavy  work. 
Four  mules  were  used  in  the  test.  They  kept  in  as 
good  condition  and  were  able  to  do  as  much  work  as 
the  four  check  animals  which  were  fed  corn  exclusively. 

Planted  in  June  and  early  July,  they  will  be  ready 

1  Geo.   W.   Carver,   Bull.   30,   Tuskegee  Normal   and   Ind.   Inst., 
p.  1. 


Utilization  of  the  Siveet  Potato  31 

for  hog-grazing  in  October.  An  acre  of  sweet  potatoes 
should  feed  eight  or  ten  hogs  weighing  200  pounds  for 
a  period  of  two  months,  provided  supplemental  feeds  are 
used  to  balance  the  ration.  Hogs  will  often  root  up 
more  than  they  will  eat  immediately  but  little  or  no 
loss  results.  It  has  been  found  that  some  of  the  heaviest 
yielding  varieties,  such  as  the  Yellow  Strasburg,  Eed 
Bermuda,  Southern  Queen  and  White  Belmont,  may  be 
left  out  in  the  field  with  but  slight  injury,  for  feeding 
purposes.  Care  should  be  taken  in  feeding  frost-bitten 
potatoes  tO'  horses,  mules  and  cattle  as  they  are  very 
sweet  at  this  time  and  stock  eat  them  ravenously. 
They  should  never  be  fed  to  any  stock  other  than  hogs 
after  they  have  become  sour.  Hogs  eat  them,  however, 
with  no  apparent  bad  results.  For  fall  and  early  win- 
ter grazing,  the  sweet  potato  is  preeminently  the  best 
crop  for  hogs  that  can  be  grown  in  the  South.  The  cut- 
over  pine  lands  of  that  region  will  doubtless  owe  their 
development  as  a  hog-raising  country  largely  to  the  fact 
that  these  soils  are  ideally  suited  to  the  growth  of  sweet 
potatoes,  which  furnish  excellent  grazing  during  the 
period  when  other  grazing  crops  are  getting  a  start  be- 
fore severely  cold  weather ;  and  to  the  perfectly  balanced 
ration  secured  when  supplemented  with  other  easily 
grown  grazing  crops,  such  as  peanuts,  soybeans,  and 
cowpea  pastures.  Such  a  combination  will  certainly 
result  in  the  production  of  economical  pork, 

Beattie  ^  has  suggested  the  production  of  excellent 
stock  feed  by  growing  some  of  the  heavy  yielding  vari- 
ties  of  sweets,  drying  and  pulverizing  them  and  adding 
enough  concentrates   to  form   a  balanced   ration.     As 

1  Farmers'  Bull.  324,  U.  S.  Dept.  Ajrr. 


33  The  Sweet  Potato 

yet  no  means  have  been  perfected  by  which  they  may 
be  converted  into  a  condensed  stock  food  on  the  fann 
economically.  It  will  be  noted  (Table  VII i)  that  both 
the  protein  and  fat-content  are  relatively  low.  If  pea- 
nuts, which  are  rich  in  these  two  elements,  are  ground 
in  the  shell  and  mixed  1  bushel  to  3  of  sweet  potatoes, 
a  well-balanced  ration  will  be  secured.  Three  bushels 
of  sweet  potatoes  are  usually  considered  equal  in  feed- 
ing value  to  1  bushel  of  com ;  but  experience  has  shown 
that  supplemental  concentrated  feeds  and  especially 
ones  rich  in  protein  should  be  used  if  a  satisfactory 
feed  is  obtained. 

Vines, 

The  vines  of  the  sweet  potato  when  properly  cured 
make  a  fair  quality  hay  for  feeding  cattle  and  sheep. 
Though  the  vines  turn  black  when  dried,  they  are  greed- 
ily eaten  by  all  kinds  of  stock.  The  principal  objec- 
tion to  saving  vines  for  hay  is  the  difficulty  of  harvest- 
ing. They  not  only  lie  flat  on  the  ground  but  root 
freely,  making  them  very  tedious  and  expensive  to 
gather.  Cattle,  hogs  and  sheep  readil}--  eat  the  green 
vines  in  the  field  but  the  food  value  is  relatively 
small  in  this  state.  In  chemical  analysis,  however, 
the  cured  vines  compare  favorably  with  some  of  our 
prominent  hays.  Keitt  ^  gives  the  following  compari- 
son of  the  average  analysis  of  red  clover,  crimson  clover, 
cowpoa  and  soybean  hays  with  that  of  hay  made  from 
sweet  potato  vines.  The  analysis  of  the  potato  vines 
represents  an  average  of  four  varieties ;  Brazilian,  Polo, 
Southern  Queen  and  l^ancy  Hall. 

1  T.  E.  Keitt,  Bull.  146,  S.  C.  Exp.  Sta.,  p.  16. 


utilization  of  the  Sweet  Potato 


33 


Table  X. —  Comparative  Analysis  of  Sweet  Potato  Vines. 


WATER-rEEB 

Protein 

Fat 

Fiber 

Ash 

Nitrogen 
Extract 

Red  clover  hay 

Crimson  clover  hay .  . . 

Cowpea    hay 

Soyabean  hay    

14.52 
10.81 
18.50 
17.36 

3.90 
3.08 
2.46 
5.86 

29.28 
30.09 
22.51 
25.14 

7.32 
9.51 
8.40 
8.12 

44.98 
40.51 
48.14 
43.52 

16.82 
12.48 

3.83 
4.80 

26.76 

18.22 

8.34 

8.73 

44.25 

Sweet  potato  vines. .  .  . 

55.71 

The  plants  with  which  the  potato  vines  are  compared 
in  the  above  table  are  among  our  most  nutritious  hays 
and  attention  is  called  to  the  fact  that  they  are  all 
legumes.  Although  the  average  protein-content  is  about 
4  per  cent  greater  than  that  contained  in  the  potato 
vines,  the  percentage  of  both  fat  and  nitrogen  free  ex- 
tract is  decidedly  in  favor  of  the  latter.  It  will  also 
be  noticed  that  the  fiber-content  is  relatively  high  in 
all  of  these  hays  compared,  which  is  of  course  the  least 
valuable  of  any  food  constituent. 

Although  analysis  shows  a  very  favorable  comparison, 
the  actual  value  as  a  hay  in  practical  feeding  is  yet  to 
be  demonstrated  by  determining  the  real  digestibility 
and  power  of  utilization  by  animals  of  the  food  con- 
stituents. 

Unless  cheap  labor  is  available  and  the  cost  of  har- 
vesting thereby  reduced,  it  will  often  be  more  profitable 
to  leave  the  vines  on  the  ground  to  decay  and  supply 
organic  matter  than  to  undertake  their  manufacture 
into  hay. 


MANUFACTURED  PRODUCTS  OF  THE  SWEET  POTATO 

The  manufacture  of  sweet  potatoes  into  various  food 
forms  which  can  be  more  systematically   handled   in 


34 


The  Sweet  Potato 


commerce  than  can  the  product  in  the  natural  state  in- 
cludes canning,  desiccating  or  dehydrating,  from  which 
process  of  reducing  the  water-content  such  by-products 
result  as  potato  flour  and  chips.  All  of  these  processes 
are  means  of  changing  the  same  food  into  a  dif- 
ferent form  that  marketing  may  be  facilitated.  In 
addition  to  these  strictly  food  manufacturing  indus- 
tries, at  least  two  other  side-line  or  strictly  speaking 
by-product  commercial  endeavors  are  possible  of  con- 
siderable development ;  one  of  these  is  the  manufacture 
of  starch  and  the  other  is  the  possibility  of  alcohol 
manufacture  from  the  fermentable  carbohydrates  con- 
tained in  the  roots. 


Dehydrated  and  desiccated  sweet  potatoes.     (Figs.  2-5.) 

In  recent  years  the  dehydration  of  various  vegetables 
has  been  undertaken  extensively  in  certain  sections  by 
numerous  manufacturing  concerns,  and  to  a  more  lim- 
ited extent  on  a  small  scale  in  the  home.     This  process 

consists  in  remov- 
ing the  water 
from  the  products 
by  means  of  heat- 
ing after  the  vege- 
tables have  been 
first  sliced  or  cut 
into  small  pieces. 
Perhaps  no  other 
one  vegetable  of- 
fers   better    possi- 

FiGURE    2. —  Showing   possible    oon-     bilities  of  develop- 
struction  of  a  commercial  sweet  potato  ^  r      ^ 

desiccating  plant.  ment    as     a     food 


utilization  of  the  Sweet  Potato 


35 


t  li  r  0  u  g  li  this 
means  than  does 
the  sweet  potato. 
The  dehydrated 
potatoes,  ready 
for  use,  appear 
in  two  forms, 
i.  e.,  sliced  and 
the  "  riced  "  or 
granulated 
forms.  The 
sliced  pieces  are 
1     to     3     inches 


Figure    3. —  A    rotary    slicer    that   may- 
be used  in  slicing  sweet  potatoes. 


long,  Vi  to  y2  inch  wide  and  about  Ys  inch  in  thickness. 
The  "  riced  "  product  appears  as  small  grains  about  the 
size  of  a  grain  of  rice.  The  sliced  article  is  very  hard 
and  usually  requires  soaking  overnight  before  using. 
Some  of  the  granulated  kinds  require  soaking  while 
others  may  be  boiled  immediately.  Both  of  these  forms 
are  used  largely  in  making  pies  and  for  seasoning  soups. 
Dehydrated  potatoes  may  be  purchased  commercially  in 
packages  ranging  from  one  pound  and  upward.  Al- 
though the  dehydrating  industry  is  still  in  its  infancy, 
it  bids  fair  to  furnish  an  excellent  medium  through 
which  sweet  potatoes  may  be  exported  and  thus  become 
of  use  in  regions  where  it  is  now  impossible  to  obtain 
them.  The  dehydrated  product  may  be  kept  indefinitely 
and  handled  as  any  other  staple  article  of  food. 

Dried  sweet  potatoes  have  for  many  years  been  pre- 
pared at  home  by  hanging  strings  of  them  from  the 
rafters  in  the  kitchen  together  with  other  drying  fruits 
and    vegetables.     This    practice    has,    however,    been 


36 


The  Sweet  Potato 


\  fN-^       •     ^^^ 

\      •  _  mP^ 


Figure  4. —  A  portable  out- 
door evaporator  to  be  heated 
by  an  ordinary  stove. 


largely  supplemented  by  preservation  in  the  modem 
farm  storage-bouses.  Many  special  devices  for  evapo- 
rating fruits  and  vege- 
tables are  on  the  market 
which  can  be  used  eco- 
nomically for  sweet  pota- 
toes. Desiccated  sweet 
potatoes  prepared  in 
much  the  same  way  as 
desiccated  white  potatoes 
are  now  sold  to  some  ex- 
tent in  everyday  com- 
merce.^ 

For  meeting  the  needs 
of  the  ordinary  family,  there  are  a  considerable  number 
of  small  driers,  both  patented  and  unpatented,  intended 

to  be  operated 
over  the  cook- 
stove  and  in  con- 
nection with  the 
usual  routine  of 
the  kitchen.^ 
Very  simple  dry- 
ing devices  may 
be  made  at  home 
by  providing  sin- 
gle racks  or  trays 
Figure  5. —  A  home-made  drier  con-  made  of  wire 
structed  of  sheet  iron  in  operation  over  a  ,    ,,  ,     , 

small  stove.  cloth    secured    to 


^^= 

1 

^ 

• 

; 

: -• 

^ 

1  Bull.  468,  U.  S.  Dept.  Agr.,  page  20;  Bull.  71,  S.  C.  Exp.  Sta., 
1903,  page  6;  Farmers'  Bull.  16!),  U.  S.  Dept.  Agr.,  1903,  page  25. 

2  For  full  description  of  various  tvpes  of   driers,  see  Farmers' 
Bull.  984,  U.  S.  Dept.  Agr. 


utilization  of  the  Sweet  Potato  37 

wooden  frames  of  the  desired  size,  and  suspended  above 
the  cookstove.  Fig.  4  shows  a  very  efficient  but  inex- 
pensive cookstove  drier  which  is  well  adapted  to  the 
desiccation  of  sweets.  A  somewhat  similar  drier  is 
shown  in  operation  in  Fig.  5.  The  housewife  will  fre- 
quently find  it  convenient  to  dry  sweets  in  the  stove  oven 
without  any  special  apparatus. 

The  desiccation  of  sweet  potatoes  is  especially  valu- 
able in  disposing  of  the  small,  extra  long  or  ill-shaped 
roots.  In  preparing  for  the  drying  process,  they  should 
be  washed  and  peeled  with  as  little  waste  as  possible, 
after  which  they  are  cut  into  slices  or  split  lengthwise 
into  quarters  or  eighths  according  to  size.  Peeling 
must  ordinarily  be  done  by  hand  or  with  a  rotary 
slicer  (Fig.  3).  The  rotary  peelers  sometimes  used  for 
Irish  potatoes  are  not  satisfactory  for  the  sweets.  The 
slices  should  be  as  near  the  same  thickness  as  possible 
to  insure  uniform  drying.  As  the  potatoes  are  sliced, 
they  should  be  blanched  by  dipping  into  boiling  water 
from  six  to  ten  minutes.  The  sliced  pieces  are  placed 
in  a  wire  basket,  or  wire-bottom  box,  to  a  depth  of  not 
over  6  inches  and  plunged  into  the  water,  which  should 
be  boiling  violently  enough  to  stir  and  separate  the 
slices.  If  cut  into  slices  y^  inch  thick,  six  to  eight 
minutes  is  sufficient  for  blanching,  but  when  cut  into 
larger  pieces  ten  minutes  is  necessary  to  secure  the  de- 
sired results.  Blanching  is  done  to  prevent  darkening 
and  it  is  desirable  to  prolong  the  blanching  process  until 
partial  cooking  results.  As  soon  as  blanched,  they 
should  be  drained  quickly  and  placed  in  the  drier.  A 
begiiming  temperature  of  145°  to  150°  F.  should  be 
used  and  as  the  product  loses  moisture,  this  should 
gradually  be  raised  to  around  160°  F.     Drying  is  com- 


38  The  Sweet  Potato 

plete  when  the  slices  become  brittle  and  break  readily 
under  pressure.  The  dried  material  is  used  for  cook- 
ing iu  the  same  way  as  other  dried  root-crops. 

Sweet  potato  flour. 

With  the  beginning  of  the  War,  every  effort  was 
made  to  determine  the  most  economical  and  convenient 
substitutes  for  wheat  flour  in  making  bread.  Among 
the  many  important  wheat  substitutes  derived  was 
sweet  potato  flour.  There  are  several  grades  of  this 
flour  and  quite  as  many  ways  to  manufacture  it.  Flour 
may  be  made  from  the  raw  potato,  from  the  cooked 
product  and  from  the  pulp  resulting  from  the  by- 
product manufacture  of  starch  (page  39). 

Sweet  potato  pie  product. 

Sweet  potato  pies  are  considered  a  delicacy  in  all  sec- 
tions of  the  South.  As  a  result  of  the  widespread  use 
for  this  purpose,  canning  factories  in  some  sections  are 
manufacturing  a  special  pie  product.  This  pie  filler  is 
put  up  in  two-  and  three-pound  tins  and  is  ready  to  be 
used  without  further  preparation.  It  is  commonly  man- 
ufactured by  peeling,  mashing  and  then  cooking  the  po- 
tatoes, after  which  a  sufficient  quantity  of  ribbon  cane 
sirup  is  mixed  with  it  to  form  a  thick  semi-fluid  sub- 
stance. The  natural  sugar  of  the  potato  and  the  cane 
sirup  combined  furnish  a  delicately  sweet  pie  filler 
which  is  rapidly  becoming  popular  over  a  wide  area. 
The  red  or  yellow  varieties  which  have  a  relatively  high 
sugar-content  are  preferred  to  the  mealy  and  less  sweet 
kinds  in  making  this  product. 


utilization  of  the  Sweet  Potato  39 

Sweet  potato  chips. 

Sweet  potato  chips  are  now  manufactured  to  a  lim- 
ited extent  by  some  dehydrating  concerns.  They  are 
put  on  the  market  in  much  the  same  form  as  the  com- 
mercial Irish  potato  chips,  which  are  packed  in  waxed 
paper  boxes.  The  sweet  potato  chips,  however,  usually 
require  other  preparation  before  using. 

Sweet  potato  sugar. 

In  addition  to  its  high  starch-content  which  is  largely 
capable  of  being  converted  into  sugars,  the  sweet  po- 
tato also  contains  several  per  cent  of  free  sugars  (more 
than  4  per  cent  of  sucrose  has  been  found  in  the  roots). 
The  fermentation  of  this  saccharine  matter  is  embodied 
in  the  manufacture  of  alcohol.  Though  the  commercial 
manufacture  of  sugar  from  this  crop  has  not  yet  been 
undertaken,  it  is  possible  that  the  next  few  years  will 
witness  concerted  effort  in  this  direction. 

Starch  manufacture. 

Carver  ^  has  described  the  home  manufacture  of 
starch  as  follows :  "  This  is  very  easily  made ;  all  that 
is  necessary  is  to  grate  the  potato,  the  finer  the  better, 
put  into  a  cheese  cloth  or  thin  muslin  bag  and  dip  up 
and  down  in  a  vessel  of  water,  squeezing  occasionally. 
Continue  washing  as  long  as  the  washings  are  milky. 
xVllow  it  to  settle  five  or  six  hours  or  until  the  water 
becomes  clear,  pour  off ;  re  wash  the  starch,  which  will 
be  in  the  bottom  of  the  vessel,  stir  up  well,  allow  to  set- 
tle again,  pour  off  the  water  and  let  it  dry.  Keep  the 
same  as  any  ordinary  starch."     Starch  made  in  this 

1  G.  W.  Carver,  Bull.  37,  Tuskegee  Normal  and  Ind.  Inst. 


40 


The  Sweet  Potato 


way  was  equal  if  not  superior  to  com-stareb  in  cooking 
and  it  was  found  that  an  excellent  quality  of  library 
paste  having  powerful  adhesive  power  could  be  manu- 
factured from  it. 

A  theoretical  yield  of  approximately  ten  pounds  of 
pure  starch  to  each  bushel  of  sweet  potatoes  has  been 
secured  in  the  laboratory  with  scientific  methods.  The 
following  table  gives  the  analyses  of  fourteen  varieties 
and  shows  an  average  of  18  per  cent  starch,  although 
it  will  be  noted  the  starch-content  varies  considerably 
with  different  varieties.  The  analyses  were  made  by 
Keitt  of  the  South  Carolina  Station  who  calls  attention 
to  the  fact  that  "  one  indication  which  appears  worthy 
of  note  is  that  the  water  content  as  a  rule  varies  from 


Table  XL — Showing  Calculated  Eate  of  Yield  per  Acre, 
Water-Content,  Starch-Content,  and  Yield  in  Pounds 
per  Acre. 


Variety 

Rate  of 
yield  per 
acre  in  Bu. 

Per 
cent. 
Water 

Per 
cent. 
Starch 

Pounds  of 
Starch 
per  Acre 

Nancy   Hall 

Polo    

Southern    Queen 

White   Spanish 

General   Grant 

Brazilian                          .  . 

270.0 
281.0 
416.0 
141.0 
191.0 
450.0 
158.0 
281.0 
214.0 
180.0 

270.0 
174.0 
141.0 
326.0 

68.75 
72.53 
68.38 
67.27 
06.52 
65.45 
72.80 
68.87 
72.12 
65.57 

62.20 

65.82 
69.84 
67.74 

17.82 
14.85 
19.07 
20.05 
17.30 
10.46 
14.43 
16.71 
13.50 
19.40 

20.63 
23.89 
19.22 
18.72 

26.94.0 
23.37.0 
44.43.0 
15.83.0 
18.50.0 
41.48.0 

Arkansas   Beauty 

Tenn  Notch  Leaf 

Yellow    Nansemond .... 

Purple    Yam 

Pumpkin   Early   Yellow 

Yam    

Shanghor    Yam 

Vineless  Bunch  Yam.  .  . 
Fullerton  Yellow  Yam. 

12.77.0 
26.29.0 
16.18.0 
19.56.0 

30.48.0 
23.28.0 
14.83.0 
34.18.0 

Average    

249.5 

8.11 

18. 

24.86.5 

Note — The  bushel  per  acre  yield  being  calculated  from  small 
areas  can  be  taken  only  as  comparative. 


utilization  of  the  Sweet  Potato  41 

65.0  and  69.0  per  cent  and  it  seems  that  any  consider- 
able increase  of  this  percentage  is  accompanied  by  a 
corresponding  decrease  in  the  starch  content  —  the  per- 
centage of  starch  being  about  as  many  per  cent  below 
the  average  as  the  water  content  is  above  the  average. 
There  are  three  striking  examples  of  this, —  the  Polo, 
the  Arkansas  Beauty  and  the  Yellow  Nansemond ;  all 
of  these  varieties  containing  over  72  per  cent  water 
and  below  15  per  cent  starch." 

White-fleshed  varieties  would  probably  be  better 
suited  to  commercial  starch  manufacture,  since  yellow 
kinds  might  discolor  the  starch.  It  is  possible  that  with 
care  in  selection,  the  starch-content  of  specific  varieties 
could  be  increased.  This  possibility  and  other  phases 
of  starch  manufacture  from  the  sweet  potato  offer  a 
wide  field  of  study  for  the  scientific  investigator. 

Alcohol  manufacture. 

When  a  solution  of  sugar  is  fermented  by  mixing 
with  a  certain  kind  of  yeast  (Mycoderma  cervisiae)  and 
kept  at  a  certain  required  temperature  until  carbon  diox- 
ide ceases  to  be  given  off,  there  is  formed  the  familiar 
substance  known  as  alcohol.  The  sugars  necessary  for 
the  fermentation  of  alcohol  may  be  obtained  from  a 
large  number  of  possible  sovirces.  In  the  commercial 
manufacture  of  this  product,  no  cheaper  means  of  pro- 
duction has  been  found  than  by  making  use  of  the 
fermentable  saccharine  matter  contained  in  such  crops 
as  rye,  barley,  wheat  and  other  grains.  A  number  of 
fruit  juices  and  vegetables  may  be  made  to  yield  alco- 
hol by  fermenting.  In  addition  to  about  18  per  cent 
starch  which  is  capable  of  fermentation  by  first  con- 


43  The  Sweet  Potato 

verting  into  sugars,  the  sweet  potato  also  contains  an 
average  of  about  4  per  cent  actual  sugar,  making  an 
average  of  about  22  per  cent  of  alcohol-producing  ma- 
terial. Keitt  found  that  a  bushel  of  sweet  potatoes 
would  produce  on  an  average  a  little  more  than  a  gallon 
of  commercial  alcohol.  As  varieties  differ  materially 
in  starch  and  sugar-content,  the  amount  of  alcohol  pro- 
duced by  a  given  quantity  of  sweet  potatoes  would 
naturally  be  influenced  by  varietal  kind.  With  the  in- 
creased demand  for  denatured  alcohol  in  art  and  science, 
it  is  probable  that  this  crop  will  furnish  an  important 
source  of  raw  material  for  manufacture. 

Sirup  from  sweet  potatoes. 

Experiments  conducted  in  the  Bureau  of  Chemistry, 
United  States  Department  of  Agriculture,  have  pro- 
duced a  palatable  and  wholesome  sirup  from  sweet  po- 
tatoes. The  method  is  recommended  particularly  for 
home  use  when  there  is  an  over-supply  of  sweet  po- 
tatoes that  cannot  be  marketed  to  advantage.  It  is  not 
advocated  at  present  for  commercial  use,  because  it  is 
believed  that  sweet-potato  sirup  cannot  compete  on  a 
commercial  basis  with  grain  sirups.  The  process  of 
manufacture  is  described  as  follows :  ^ 

"  The  sweet  potatoes  should  be  washed,  any  decayed 
portions  or  other  blemishes  removed,  and  then  weighed. 
They  are  then  placed  in  a  kettle  with  plenty,  of  water 
and  boiled  until  thoroughly  soft.  From  II/2  to  2  hours' 
boiling  is  required.  The  potatoes  are  then  mashed  in 
the  kettle  in  the  water  in  which  boiled,  with  sufficient 
water,  adding  more  if  necessary  to  form  a  thick,  smooth, 
mushy  liquid.  The  temperature  of  the  mixture  is  then 
1  "  Weekly  News  Letter,"  U.  S.  Dept.  Agr.,  Feb.  12,  1919,  p.  6. 


utilization  of  the  Sweet  Potato  43 

brought  to  140°  F.,  and  a  quantity  of  ground  malt 
added  equal  to  31A  per  cent  of  the  weight  of  the  orig- 
inal sweet  potatoes.  The  mixture  is  thoroughly  stirred 
and  allowed  to  stand  for  a  few  minutes  at  a  temperature 
of  140°  F.,  and  the  temperature  is  then  brought  with 
constant  stirring  to  a  temperature  of  150°  F.,  the 
source  of  heat  removed,  and  the  mass  allowed  to  stand 
with  occasional  stirring  for  an  hour.  The  mixture, 
known  technically  as  the  '  mash,'  is  now  pressed  in 
cloths  to  separate  the  liquid  and  solid  portions.  The 
material  is  placed  in  cloth  bags,  which  are  closed,  and 
the  bags  subjected  to  gentle  pressure  while  kneeding. 
The  juice  flows  out  readily,  leaving  the  pulp  behind. 
The  juice  is  now  boiled  down  to  sirup  in  an  ordinary 
kettle. 

"  Any  of  the  common  varieties  of  sweet  potatoes  can 
be  used.  Freshly  harvested  stock  will  yield  a  sirup 
somewhat  less  sweet  than  sweet  potatoes  which  have 
been  harvested  for  some  time. 

"  The  sweet  potatoes  should  be  cooked  with  plenty 
of  water.  It  is  necessary  to  obtain  a  fluid,  mushy  mass 
which  can  be  mixed  readily  with  the  malt. 

"  Great  care  must  be  taken  that  the  temperature  of 
the  mass  be  uniform  throughout  during  the  action  of 
the  malt. 

"  Ordinary  brewer's  or  distiller's  malt  of  good  qual- 
ity gives  excellent  results,  or  the  malt  can  be  made  by 
sprouting  barley  under  proper  conditions.  In  prepar- 
ing malt  from  barley  the  following  method  will  give 
satisfactory  results:  The  grain  should  be  soaked  in 
water  for  12  hours.  The  water  is  then  drained  off  and 
the  grain  allowed  to  stand  for  12  hours,  and  the  opera- 
tion of  soaking  and  standing  repeated  during  the  next 


44  The  Sweet  Potato 

24  hours.  At  the  conclusion  of  the  steeping,  the  in- 
terior of  the  grain  should  be  soft  and  chalklike.  The 
grain  is  then  spread  upon  a  tray  in  a  layer  not  over 
6  or  8  inches  deep.  The  temperature  at  which  the 
sprouting  grain  is  kept  is  of  great  importance  in  the 
successful  manufacture  of  malt.  It  should  be  kept  as 
near  60°  F.  as  possible.  After  the  grain  has  grown 
for  six  or  eight  days  the  sprout  forces  its  way  out  at 
the  end  of  the  grain  opposite  to  the  rootlet,  and  the  malt 
may  be  used  with  excellent  results  at  this  time.  Sprout- 
ing, however,  may  be  allowed  to  continue  slowly  for 
another  six  or  eight  days,  or  even  longer,  until  the 
sprout  has  attained  a  length  from  three  to  four  times 
that  of  the  grain.  The  grain  must  be  kept  moist,  so 
that  the  rootlets  do  not  wither  during  the  sprouting 
period  and  should  be  turned  over  and  thoroughly  mixed 
at  least  once  a  day  and  kept  covered  with  a  wet  cloth 
and  in  the  dark.  The  product  is  known  as  '  green  malt.' 
It  should  have  a  fresh  odor  and  be  free  from  any  sour 
smell,  and  should  be  free  from  mold.  Immediately  be- 
fore use  the  green  malt  should  be  finely  ground  in  an 
ordinary  meat  chopper  or  other  suitable  machine. 
When  so  ground  it  forms  a  pasty  mass  and  may  be 
added  directly  to  the  boiled  mashed  sweet  potatoes  and 
the  mixture  thoroughly  broken  up  by  stirring  until  the 
malt  is  thoroughly  disseminated. 

"  On  a  small  scale  this  is  most  readily  accomplished 
as  described.  On  a  large  scale  an  ordinary  cider  press, 
using  racks  and  cloths,  can  be  successfully  employed. 
The  liquid  obtained  is  slightly  sweet  and  rather  turbid. 
Plenty  of  water  should  be  used  in  order  to  produce  a 
mash  from  which  the  liquor  will  freely  flow  and  in 
which  a  large  proportion  of  the  sugars  may  be  easily 


utilization  of  tlt.e  Sweet  Potato  45 

removed  by  a  single  pressing.  The  total  quantity  of 
water  used  should  be  two  or  three  times  the  weight  of 
the  potatoes.  The  sweet-potato  sirup  can  be  boiled 
down  to  as  thick  a  consistence  as  desired.  The  pulp 
which  remains  can  be  dried  and  used  for  feed,  or  it  can 
be  fed  while  fresh." 

Canned  sweet  potatoes. 

The  commodity  in  this  form  is  now  finding  a  wide 
and  ready  sale  over  the  entire  country.  There  are 
many  canning  factories  in  the  South  and  Southeast, 
especially  along  the  coast  lines  where  fish  products  may 
be  obtained  during  the  season  when  potatoes  are  scarce. 
These  industries  are  opening  up  an  extensive  trade 
which  has  not  been  developed  before.  Practically  every 
town  along  the  Gulf  Coast  has  one  or  more  canning  fac- 
tories which  handle  sweet  potatoes  exclusively  during 
a  large  part  of  the  year.  The  commercially  canned 
product  appears  in  two-  and  three-pound  tins.  They 
may  be  cooked  in  any  way  except  baked,  as  they  are 
peeled  and  somewhat  mashed  in  the  canning  process. 
The  red  or  yellow  varieties  are  preferred  for  canning 
because  of  the  dark  color  assumed  by  the  white  po- 
tatoes after  cooking. 

J.  H.  Barrett  and  Son,  manufacturers  of  canned 
goods  at  Westminster,  South  Carolina,  who  are  among 
the  most  successful  eanners  of  sweet  potatoes  in  the 
South,  have  given  the  following  method  for  steam  can- 
ning: 

"  I  have  been  packing  sweet  potatoes  for  over  ten 
years  and  I  lose  very  few  cans,  not  over  one  or  two  to 
the  thousand.  I  peel  the  raw  potatoes  on  an  Imperial 
machine,  cutting  the  large  potatoes  in  several  pieces, 


46  The  Sweet  Potato 

making  them  a  uniform  size  so  that  the  entire  cooking 
will  be  thoroughly  done  at  the  same  time.  I  cook  in 
a  copper  kettle  using  steam,  without  any  water  as  the 
steam  makes  enough  moisture.  After  the  potatoes  are 
thoroughly  cooked  I  remove  them  from  the  kettle  and 
pack  them  in  cans,  filling  the  can  full  of  soft  cooked 
potatoes,  then  I  cap  and  cook  the  potatoes  one  hour  at 
2(30  dgrees  of  heat,  then  remove  the  potatoes  from 
cooker  immediately  and  let  them  cool.  If  you  will 
carry  out  this  method  your  potatoes  will  keep  all  O.K., 
but  do  not  let  your  potatoes  remain  out  too  long  from 
the  first  cooking  in  the  kettles  until  you  cook  them  the 
second  time  —  not  over  one  hour." 

Other  canning  recipes  with  steam  pressure  canning 
machines  and  tin  cans  are :  ^ 

Eecipe  No.  1. — Boil  or  steam  potatoes  until  three-fourths 
done;  peel  and  pack  dry  into  No.  3  cans,  being  sure  to  get 
full  pack,  then  seal.  Exhaust  8  to  10  minutes  at  boiling  tem- 
perature and  tip.  Cook  or  process  these  cans  70  minutes  at 
10  pounds  pressure. 

Recipe  No.  2. —  Cook  potatoes  until  thoroughly  done; 
skin  and  mash  with  an  ordinary  masher.  Pack  solidly  into 
cans  and  finish  as  in  recipe  No.  1.  If  No.  2  cans  are  used 
for  the  mashed  potatoes,  they  should  be  cooked  55  minutes 
instead  of  70  minutes. 

Canning  with  glass  jars  and  hot  water  is  not  so 
satisfactory  as  when  steam  canning  facilities  are  avail- 
able. 

DOMESTIC    COOKING    OF    SWEET    POTATOES 

It  is  thought  by  many  that  sweet  potatoes  are  at  their 

best  when  prepared  in  the  simplest  way,  that  is,  cooked 

1  Miss  Cornelia  Simpson,  canning  specialist,  Tex.  A.  &  M.  Coll. 


utilization  of  the  Sweet  Potato  47 

or  boiled.  Even  so,  a  very  wide  variety  is  possible,  for 
it  lias  been  said  that  sweet  potatoes  may  be  prepared 
in  more  than  a  hundred  ways.  Specific  ways  of  prepa- 
ration will  be  given  as  briefly  as  possible.  The  recipes 
contained  herein  have  been  carefully  selected  from  the 
great  bulk  of  information  published  because  of  their 
practicability  and  ease  of  execution;  these  have  been 
thoroughly  tried  out  and  recommended  by  the  United 
States  Department  of  Agriculture  and  food  specialists 
of  the  various  state  departments  of  agriculture. 

Northern  and  southern  tastes  differ  as  to  what  is  a 
desirable  quality  in  a  sweet  potato.  The  moist  sweet 
varieties  are  preferred  in  the  South  while  the  North 
generally  prefers  a  dry  mealy  root.  Long  cooking  will, 
however,  make  any  sweet  potato  moist. 

("  T  "  indicates  tablespoons.) 

BAKED    SWEET    POTATOES 

Wash  the  potatoes  and  bake  the  same  as  white  potatoes. 
Small  ones  will  bake  in  half  an  hour,  while  very  large  ones 
will  require  an  hour  or  more.  If  the  potatoes  are  desired 
very  moist  and  sweet,  bake  from  1  hour  to  2  hours  depending 
on  size. 

BROWNED   SWEET    POTATOES 

Boil  medium-sized  sweet  potatoes  45  minutes.  Peel  them 
and  cut  in  halves  lengthwise.  Put  them  in  a  baking  pan  and 
baste  with  savory  drippings,  and  season  with  salt.  Cook 
them  in  a  hot  oven  for  20  minutes. 

FRIED    SWEET    POTATOES 

Parboil  the  potatoes,  peel,  cut  in  slices,  and  fry  to  a  nice 
brown  in  boiling  lard.  They  can  be  fried  without  boiling, 
though  it  will  require  a  longer  time  and  more  lard  or  butter. 


48  The  Sweet  Potato 

CANDIED   SWEET    POTATOES 

Candied  sweet  potatoes  are  very  popular  on  southern 
tables,  and  are  extremely  palatable  when  well  prepared. 
Cut  boiled  sweet  potatoes  into  long  slices,  place  in  an  earthen 
dish,  put  lumps  of  butter  on  each  slice,  and  sprinkle  with 
sugar.  Some  cooks  add  a  little  water  also.  Bake  until 
the  sugar  and  butter  have  candied  and  the  potatoes  are 
brown. 

SWEET    POTATO    BISCUIT 

V2  cupful  mashed  sweet  potatoes,  1  cupful  flour,  4  tea- 
spoons baking-powder,  V2  teaspoon  salt,  2  tablespoons  butter 
or  lard,  milk  sufficient  to  make  a  soft  dough.  Sift  the  flour, 
salt,  and  baking-powder  together  several  times;  add  these 
to  the  potatoes,  mixing  in  with  a  knife.  Now  work  the  fat 
into  the  mixture  lightly;  add  the  milk;  work  quickly  and 
lightly  until  a  soft  dough  is  formed;  turn  out  on  a  floured 
board;  pat  and  roll  out  lightly  until  about  one-half  inch 
thick;  cut  into  biscuits;  place  on  buttered  or  greased  pans, 
and  bake  12  or  15  minutes  in  a  quick  oven. 

SWEET   POTATO   BREAD 

(Enough  for  two  large  loaves).  G  cups  sifted  flour  (more 
if  flour  is  soft),  2  cups  mashed  sweet  potato  (luke-warm), 
y2  cup  lukewarm  water  (this  will  not  be  required  if  liquid 
yeast  is  used),  1  cake  yeast,  dry  or  compressed  or  Vo  cup 
liquid  yeast,  1  T  sugar,  1  T  salt,  2  T  shortening,  if  desired. 
To  the  cool  mashed  potato  add  the  salt,  the  sugar,  and  about 
4  ounces  of  the  flour  (1  scant  half  pint  of  sifted  flour),  and 
mix  thoi'oughly.  Next  add  the  yeast,  which  has  been  rubbed 
smooth  in  a  cup  with  4  tablespoons  of  lukewarm  water. 
To  get  all  the  yeast,  rinse  the  cup  with  the  remainder  of  the 
half  cup  of  water  and  add  this  also  to  the  potato.  Cover  and 
place  the  bowl  out  of  the  way  of  drafts  and  at  a  temperature 
of  80°  to  88°  F.  Allow  this  mixture  to  rise  for  two  hours 
or  until  very  light. 

To  this  sponge  add  the  melted  shortening  and  the  re- 
mainder of  the  flour,  kneading  thoroughly  until  a  smooth 
and  elastic  dough  has  been  formed.     Do  not  add  more  water 


utilization  of  the  Sweet  Potato  49 

to  the  dough  unless  it  is  absolutely  necessary  in  order  to 
incorporate  all  the  flour.  Set  the  dough  back  to  rise  again 
for  1  hour  or  until  light.  Bake  allowing  it  to  rise  in  the 
pans  only  until  two  and  one-half  times  the  original  volume. 
If  desired  the  sponge  for  this  bread  may  be  set  in  the 
evening  using  only  one-fourth  as  much  yeast  as  directed  for 
the  quicker  method.  In  warm  weather  keep  this  sponge  cool. 
Rolls  may  be  made  from  this  mixture. 

SWEET    POTATO   MUFFINS 

IV2  cups  cooked  sweet  potato  (Irish  potatoes  may  be  used 
instead,  with  or  without  the  sugar),  IV2  cups  sifted  white 
flour,  1  teaspoon  salt,  2  teaspoons  baking-powder,  2  T  sugar, 
2  eggs,  2  T  shortening,  liquid  sufficient  to  make  a  rather  stiff 
batter  (about  Vs.  cup).  Boil  the  potatoes  in  the  skins  until 
tender,  drain,  peel  and  mash  fine.  Putting  the  potato 
through  a  ricer  or  colander  is  better  than  mashing.  Sift 
together  the  flour,  salt,  sugar  and  baking-powder  twice. 
Beat  the  eggs  until  light  and  add  to  the  cool  mashed  potato. 
Next  add  the  melted  shortening,  then  the  flour  mixture, 
alternating  with  portions  of  the  liquid,  until  a  batter  is 
formed  somewhat  stiffer  than  for  ordinary  flour  muffins. 
Drop  by  spoonfuls  into  greased  muffin  pans  until  half  filled 
and  bake  20  to  25  minutes  in  a  fairly  hot  oven. 

SWEET  POTATO   SALAD 

Cut  hot  boiled  sweet  potatoes  into  very  small  pieces.  To 
1  cup  diced  potatoes  add  Mj  cup  chopped  peanuts  and  1  T  of 
thin  mayonnaise  or  French  dressing.  Arrange  on  lettuce 
leaves  and  garnish  with  stiff  mayonnaise. 

SWEET   POTATO   PEANUT   CROQUETTES 

3  cups  mashed  potato,  IV2  teaspoons  salt,  2  T  fat,  1  egg 
(beaten  slightly),  %  cup  chopped  nuts,  and  a  little  milk  if 
mixture  is  too  stiff.  Shape  into  croquettes.  Dip  in  crumbs, 
beaten  egg,  into  crumbs  again  and  fry  in  deep  fat.  Drain 
and  serve  hot. 


50  The  Sweet  Potato 


BAKED    SWEET    POTATO   CUSTARD 

1  egg,  IV2  cups  scalded  milk,  ^2  cup  mashed  sweet  potato, 
I/2  teaspoon  vanilla,  2  T  sugar.  Beat  egg,  add  sugar,  mashed 
potato  and  scalded  milk.  Pour  into  greased  individual  bak- 
ing dishes,  place  in  pan  of  hot  water  and  hake  until  set. 
Raisins  or  nuts  may  be  added.     Serve  with  caramel  sauce. 

SWEET  POTATO  A  LA  AGNES 

If  you  use  grate  or  open  wood  fires,  this  will  prove  an 
attractive  supper  dish.  Bury  the  sweet  potatoes  in  the  ashes 
and  cover  with  coals  or  allow  to  stand  under  grate.  Roast 
for  about  two  hours.  The  skin  will  be  very  dark  when  fin- 
ished. Remove  from  ashes,  wipe  off  potatoes,  open  the  skin 
and  take  out  potato.  Serve  hot  with  a  spoonful  of  mayon- 
naise dressing  on  each  potato. 

SWEET    POTATO   WITH    RAISINS   AND    MARSHMALLOWS 

2  cups  mashed,  boiled,  or  baked  sweet  potato,  3  T  butter, 
1/2  teaspoon  salt,  hot  milk  enough  to  moisten.  Beat,  adding 
%  cup  chopped  raisins  or  prunes.  Pour  into  greased  baking 
dish,  brush  top  with  milk,  and  brown  in  oven.  Just  before 
removing  from  oven  stick  marshmallows  half  way  into  mix- 
ture and  keep  in  oven  until  marshmallows  have  toasted. 
Serve  hot. 

The  marshmallows  and  raisins  may  be  omitted  and  the 
potatoes  served  as  mashed  potatoes.  The  mashed  potatoes 
may  be  varied  by  adding  a  sirup  of  2  T  molasses  and  1  T 
butter  cooked  together  for  five  minutes.  This  can  be  poured 
over  the  mashed  potatoes,  and  bake  until  they  are  very 
brown. 

SWEET    POTATO   DEVIL's    FOOD 

1  cup  mashed  sweet  potato,  ^A  cup  sugar,  y^  cup  fat,  2  tea- 
spoons milk,  1  egg,  I/4  cup  raisins,  V-i  cup  hickory-nuts,  1  cup 
flour,  4  teaspoons  baking-powder,  2  teaspoons  melted  choco- 
late, 1  teaspoon  cinnamon,  I/2  teaspoon  cloves,  V2  teaspoon 
nutmeg,  Va  teaspoon  salt. 

Cream  fat,  sugar,  add  beaten  egg,  mashed  potato,  melted 
chocolate,  milk.     Sift  flour  and  measure.     Add  other  dry  in- 


utilization  of  the  Sweet  Potato  51 

gredients  to  flour  and  sift  into  mixture.  Add  nuts  and 
raisins.  Bake  in  greased  pans  and  combine  in  and  frost 
two  layers  with  the  following  frosting:  Vs  cup  water,  1  cup 
sugar,  1  egg,  Vo  teaspoon  vanilla.  Cook  water  and  sugar  to- 
gether until  the  sirup  threads  when  dropped  from  a  spoon. 
Eemove  from  fire  and  beat  into  stiffly  beaten  egg-white.  Add 
vanilla  and  beat  until  consistency  to  spread. 

SWEET    POTATO   DROP   COOKIES 

2  cups  mashed  sweet  potatoes,  iVi  cups  sugar,  4  teaspoons 
baking-powder,  1  teaspoon  cloves,  V2  cup  raisins,  1  egg,  I/2 
cup  fat,  2  cups  flour,  1  teaspoon  cinnamon,  V2  teaspoon  nut- 
meg, 1  teaspoon  salt.  Cream  fat  and  sugar.  Add  beaten 
egg,  mashed  potatoes,  dry  ingredients  sifted  together  and 
raisins.  Drop  from  spoon  on  greased  tin  and  bake  in 
moderately  hot  oven. 

BOILED    SWEET    POTATOES 

The  roots  are  washed  and  boiled  as  Irish  potatoes,  but  with- 
out peeling.  When  sufficiently  done  to  permit  piercing  with 
a  straw,  take  up  and  peel;  when  large,  cut  lengthwise;  place 
in  covered  dish  and  pour  melted  butter  over  them.  Boiling 
is  especially  popular  in  the  North  where  the  varieties  grown 
are   commonly   dry   and   mealy. 

SLICED   AND   BAKED   SWEET    POTATOES 

Slice  roots  that  have  been  boiled  until  nearly  done,  place 
butter  sprinkled  with  sugar  between  slices;  continue  layer  of 
butter  and  sugar  and  potato  slices  alternately  until  baking 
dish  is  full.  Add  a  small  quantity  of  water  and  bake 
thoroughly. 

RICED    SWEET    POTATOES 

Force  boiled  sweet  potatoes  through  a  ricer,  or  a  coarse 
strainer  into  a  hot  vegetable  dish.  Avoid  rehandling  in  order 
to  keep  the  potatoes  light  and  attractive  in  appearance. 
Eiced  sweet  potatoes  are  particularly  appropriate  with  roast 
beef,  roasted  chicken  or  any  meat  served  with  gravy. 


52  The  Sweet  Potato 


SWEET    POTATO    FLOUR 


There  are  several  grades  of  this  product  and  quite  as  many- 
ways  to  manufacture  them.  Each  one  of  these  flours  or 
meals  (as  most  millers  insist  on  calling  them)  has  a  particu- 
lar character  of  its  own  and  is  therefore  adapted  to  certain 
uses  the  other  products  are  not.  The  sweet  potato  flours  are, 
generally  speaking,  of  three  kinds :  (1)  Those  made  from  the 
uncooked  potato;  (2)  those  made  from  the  cooked  potato; 
(3)  those  made  from  a  careful  system  of  roasting,  or  from  the 
starch  making  process.  The  first  two  will  be  of  most  interest 
to  the  housewife. 

FLOUR  NO.    1  FROM   THE  RAW   POTATO 

Here  all  that  is  necessary  is  to  wash,  peel,  and  slice  the 
potatoes  very  thin,  dry  in  sun,  oven  or  dryer  until  the  pieces 
are  quite  brittle,  grind  very  fine  in  a  coffee  or  spice  mill,  or 
any  type  of  mill  that  will  make  wheat  flour  or  corn-meal; 
bolt  through  fine  cloth  in  the  same  way  as  for  other  flours. 
The  fine  flour-like  particles  will  pass  through,  and  the  coarse 
granular  meal  left  on  the  bolting  cloths.  This  kind  of  flour 
is  good  for  making  mock  rye  bread,  ginger  snaps,  wafers, 
waffles,  batter  cakes,  custards,  pies,  and  the  like.  Bread  can  be 
made  with  it,  but  it  makes  a  dough  deficient  in  elasticity, 
bread  dark  in  color  and  a  loaf  which  dries  out  quickly. 

The  coarser  meals  can  be  cooked  in  a  great  variety  of 
ways  and  make  very  palatable  dishes;  they  are  to  be  soaked 
in  warm  liquid  (whatever  is  desired  to  cook  them  in),  when 
soft  proceed  as  for  grated  potatoes. 

FLOUR   NO.    2   FROM   COOKED   POTATOES 

For  the  making  of  this  flour  the  potatoes  are  boiled,  or 
steamed  (preferably  the  latter)  until  done,  sliced  or  granu- 
lated by  mashing  or  running  through  a  food  chopper  and 
dried  until  they  become  very  brittle.  They  are  made  into 
flour  and  meal  exactly  the  same  as  given  for  Flour  No.  1. 
This  kind  of  flour  is  especially  good  for  bread,  cakes,  pies, 
puddings,  sauce,  gravies,  custards,  and  so  on.  A  loaf  may 
be  made  in  the  proportion  of  one-third  sweet  potato  flour  to 


utilization  of  the  Sweet  Potato  53 

two-thirds  wheat  flour.  Many  experiments  have  proven  that 
either  the  maslied  sweet  potato  or  the  sweet  potato  flour  may 
be  used  in  bread  as  high  as  50  per  cent  but  at  this  point  it 
becomes  decidedly  potato-like  in  texture  and  flavor  but  not 
unpalatable  or  unwholesome. 

FLOUR  NO.    3   FROM    PULP 

This  flour  is  make  from  the  pulp  after  the  starch  has  been 
removed.  It  is  dried  without  cooking,  ground  and  bolted 
exactly  the  same  as  recommended  for  the  other  flours.  When 
made  into  puddings,  pies,  blanc-mange,  and  the  like,  the 
same  as  shredded  eocoanut,  it  resembles  it  very  much  in  taste 
and  texture  and  is  very  palatable  and  is  a  most  welcome 
addition  to  the  dietary.  It  can  also  be  used  in  the  making  of 
bread  and  is  especially  valuable  when  a  loaf  is  desired  with- 
out the  least  sweet  taste,  and  with  as  little  starch  and  sugar 
as  possible. 

SWEET   POTATO  STARCH 

This  is  very  easily  made,  all  that  is  necessary  is  to  grate 
the  potato,  the  finer  the  better,  put  into  a  cheese-cloth  or  thin 
muslin  bag  and  dip  up  and  down,  in  a  vessel  of  water, 
squeezing  occasionally,  continue  washing  as  long  as  the  wash- 
ings are  very  milky.  Allow  it  to  settle  five  or  six  hours  or 
until  the  water  becomes  clear,  pour  off;  rewash  the  starch, 
which  will  be  in  the  bottom  of  the  vessel,  stir  up  well,  allow 
to  settle  again,  pour  off  the  water  and  let  dry;  keep  the  same 
as  any  ordinary  starch.  Used  exactly  the  same  as  corn- 
starch in  cooking.  As  a  thickening  agent,  1  tablespoon  of 
sweet  potato  starch  thickens  1  cup  of  licpiid  to  the  consistency 
of  a  tliiek  sauce  or  makes  a  pudding  of  the  proper  con- 
sistency for  molding. 


CHAPTER  IV 

PROPAGATION 

The  sweet  potato  produces  seed  in  ISTorth  America 
only  when  the  growing  season  is  prolonged  by  artificial 
means.  The  more  common  varieties  are  propagated 
by  means  of  sets  taken  from  the  tubers  (called  "  seed  ") 
themselves  and  from  cuttings  or  vines  from  the 
growing  crop.  The  "  draws,"  as  they  are  commonly 
called  in  the  South,  are  produced  by  bedding  the  tubers 
in  a  specially  prepared  bed  where  they  are  sprouted 
and  the  young  plants  removed  three  or  four  times  as 
they  appear,  being  set  in  the  field  as  would  the  seed- 
lings of  cabbage,  tomatoes  or  similar  plants.  This 
practice  furnishes  the  most  economical  method  of  propa- 
gation. The  tubers  themselves  are  sometimes  planted 
directly  in  the  field  where  they  are  to  grow  in  much 
the  same  way  as  with  the  common  potato.  When  this 
method  is  employed,  several  plants  often  appear  in  one 
hill,  which  necessitates  thinning.  Its  use  is  restricted 
to  special  areas  or  to  cases  influenced  by  peculiar  con- 
ditions. Propagation  by  vine-cuttings  has  been  prac- 
ticed quite  extensively  and  very  satisfactorily  in  all  of 
the  southern  states.  This  practice  is  especially  popu- 
lar for  the  late  crop  and  there  are  several  arguments  in 
favor  of  its  more  extensive  use  in  controlling  disease, 
in  the  production  of  potatoes  to  be  stored,  and  in  render- 
ing production  more  economical.     At  a  sweet  potato 


rropagaiion  55 

conference  held  in  connection  with  the  annual  meeting 
of  the  Association  of  Southern  Agi-icultural  Workers 
in  Birmingham,  Alabama,  in  1919,  the  terms  "  slips," 
"  sprouts,"  "  draws  "  and  ''  plants  "  were  officially  de- 
cided on  as  designating  plants  derived  from  bedded  po- 
tatoes, while  "  cuttings  "  and  "  vine-cuttings  "  should 
refer  to  the  cut  ends  of  vines  used  for  rooting. 

In  the  extreme  southern  part  of  the  United  States, 
notably  in  southern  Florida  and  also  in  some  of  the 
neighboring  tropical  islands,  the  potatoes  are  sometimes 
left  in  the  ground  from  one  year  to  another.  This 
practice  would  be  more  widely  followed  but  for  the 
excess  water  often  present  in  the  soil  in  these  southern 
areas,  which  causes  the  tubers  to  rot.  In  a  dry  season 
or  on  high  ground  even  near  the  water  where  the  winters 
are  always  mild,  as  in  southern  Florida,  the  crop  may 
remain  in  the  ground  without  injury.  In  such  cases, 
the  tubers  are  removed  for  use  as  needed  and  in  the 
spring  those  which  are  left  sprout  and  produce  slips 
which  may  be  transplanted  or  allowed  to  remain  on 
the  same  ground. 

By  far  the  most  important  method  of  propagation  and 
that  which  is  primarily  depended  on  by  practically  all 
commercial  growers  of  this  country,  is  the  use  of 
plants  produced  in  the  artificial  or  preliminary  seed- 
bed. In  fact,  the  recent  gain  in  popularity  of  the 
sweet  potato  as  a  food  crop  has  created  such  a  demand 
for  sweet  potato  plants  of  pure  varieties  by  the  general 
public,  that  individual  growers  have  found  the  "  slip  " 
business  a  very  profitable  commercial  enterprise.  In 
many  sections  individuals  have  developed  this  business 
into  an  industry  of  no  mean  economical  importance. 
Several  dealers  in  the  Central  West  bed  annually  more 


56  The  Sweet  Potato 

than  10,000  bushels  of  tubers,  selling  the  plants  to 
smaller  growers  at  a  good  profit.  This  specialization 
has  not  only  been  made  remunerative  by  ingenious  and 
industrious  planters,  but,  because  of  the  economy  pos- 
sible in  handling  large  quantities,  has  been  of  real 
service  to  the  smaller  planters.  The  larger  number  of 
farmers  who  plant  less  than  an  acre  usually  find  it 
more  convenient  and  economical  to  purchase  their  plants 
than  to  grow  them  at  home.  Planters  growing  more 
than  an  acre  usually  prefer  to  prepare  their  own  seed- 
bed and  grow  their  sets  at  home.  From  6  to  8  bushels 
of  seed  potatoes  are  required  to  produce  enough  plants 
to  set  an  acre  at  one  drawing.  Usually  three  or  four 
drawings  may  be  made,  3  or  4  bushels  of  seed  producing 
enough  plants  for  an  acre.  It  requires  from  8,000  to 
10,000  plants  to  set  an  acre  (Plate  III).  Although  as 
many  as  4,000  plants  have  been  produced  from  a  single 
bushel  of  seed,  the  average  production  ranges  from  one- 
third  to  one-half  this  number  with  three  or  four  draw- 
ings. The  question  of  proper  seed  selection  with  refer- 
ence to  the  influence  on  yield  and  quality  of  the  field 
product  and  the  control  of  disease  is  now  known  to  be 
of  more  importance  than  was  formerly  thought. 

SELECTING  SEED  (l.  E.,  TUBERS  FOR  PROPAGATING) 

Although  the  value  of  individual  hill  selection  has 
been  fully  demonstrated  with  the  common  potato,  ex- 
perimental data  available  on  the  same  subject  with  the 
sweet  potato  is  not  so  complete.  The  commonly  fol- 
lowed practice  of  using  the  culls  and  stringy  tubers  for 
seed  has  been  the  subject  of  much  controversy  with 
little  conclusive  data  substantiating  either  side  of  the 
argument.     However,     practical    growers    have    long 


Platk  III. —  Sweet  potato  field  operations,  a,  A  field  of 
sweet  potatoes  after  the  vines  have  practically  covered  the 
ground,  b.  Droppincr  and  setting  draws  by  hand.  c.  A  horse- 
drawn  fertilizer  distributor  in  operation. 


Propagation  57 

recognized  the  importance  of  seed  selection  as  a  means 
of  controlling  disease  and  popular  opinion  seems  to 
have  indicated  merit  in  the  theories  commonly  advanced 
with  reference  to  the  influence  of  more  careful  selec- 
tion over  yield  and  characteristics  of  the  resulting  crop. 
Eecent  experiments  on  the  eastern  shore  of  Virginia 
have  strengthened  this  belief.  There  are  several  con- 
siderations in  selecting  seed  which  plain  judgment  would 
dictate  as  being  worthy  of  practical  execution  for  the 
sake  of  a  conservative  system  on  the  farm  if  for  no 
other.  One  of  the  greatest  hindrances  to  systematic 
marketings,  especially  from  the  more  southern  areas, 
is  the  mixed  condition  of  the  varieties.  As  the  only 
means  of  mixing  is  by  mechanical  mixture  of  the  tubers 
themselves,  this  condition  is  inexcusable.  It  can  be 
entirely  eliminated  by  careful  selection  and  handling 
of  the  seed  stock. 

Selecting  "seed"  (tubers)  for  disease  control. 

Seed  selection  is  of  the  very  first  importance  in  sweet 
potato  growing  from  the  standpoint  of  controlling  dis- 
eases. A  number  of  diseases  seriously  affect  the  crop 
in  the  field  and  unless  care  is  taken  to  choose  clean 
healthy  seed,  these  diseases  may  be  carried  into  storage 
and  later  into  the  seed-bed  where  they  are  transmitted 
to  the  propagating  plant  stock.  One  of  the  greatest 
troubles  in  the  way  of  a  successful  storage  is  the  bring- 
ing in  from  the  field  of  decay  organisms  which  would 
never  have  been  present  had  proper  precautions  been 
taken  in  selecting  the  seed  which  produced  the  field 
crop.  A  comparatively  short  time  ago  sweet  potato 
diseases  were  practically  unknown,  but  now  it  is  often 
difficult  to  secure  disease-free  seed.     Many  of  the  dis- 


58  The  Sweet  Potato 

eases,  such  as  soil-stain  and  foot-rot,  can  be  controlled 
eifectively  by  selection  and  the  danger  even  from  soft- 
rot  and  black-rot  can  be  greatly  lessened  by  careful 
culling  and  the  use  of  proper  disinfecting  agencies  on 
the  seed  to  be  bedded.  (Chapter  VIII.)  Only  sound 
potatoes  free  from  soft  spots  should  be  selected  for  bed- 
ding. Tubers  with  suspicious  looking  spots  should  be 
avoided  for  seed  purposes.  It  is  best  to  obtain  these 
seed  from  plots  known  to  be  free  from  field  diseases. 
Freedom  from  disease  should  be  the  governing  factor 
in  selection  rather  than  disease  resistance.  The  tubers 
for  bedding  should  be  selected  at  time  of  harvesting, 
carefully  handled  to  prevent  bruising  and  consequent 
infection  by  disease,  and  carefully  stored  to  prevent 
freezing  and  injury  from  other  sources. 

For  yield  and  quality. 

It  is  now  commonly  recognized  that  the  only  basis 
for  the  improvement  of  the  sweet  potato  is  the  hill 
unit.  Bin  selection  is  not  sufficient.  Hill  selection, 
followed  for  two  years  on  the  eastern  shore  of  Virginia, 
practically  doubled  the  yield.  ^  The  practice  in  Vir- 
ginia is  to  select  from  hills  with  five  or  more  marketable 
potatoes.  Quicker  results  will  be  secured  if  the  stand- 
ard is  placed  higher  and  selection  made  from  hills  show- 
ing ten  or  more  marketable  potatoes.  The  market  de- 
mands a  smooth,  medium-sized,  spindle-shaped  potato; 
and  this  standard  should  be  kept  in  mind  in  selecting 
the  seed  stock,  although  use  of  the  small  tubers  from 
high  yielding  hills  seems  to  have  no  bad  effect. 

1  Report  of  the  conference  on  sweet  potato  problems  and  on 
diseases  of  cotton,  corn  and  tomatoes,  Birmingham,  Ala.,  Feb., 
1919. 


Propagation  59 

Small  or  medinm-sized  roots  are  usually  selected  for 
seed  purposes  since  the  small  roots  produce  many  more 
plants  to  a  bushel  of  seed  than  do  larger  potatoes.  It 
would  seem  reasonable  to  believe  that  continued  use  of 
small  seed  would  tend  toward  the  production  of  a  field 
crop  of  small  tubers  but  this  theory  has  not  been  sub- 
stantiated in  practice.  The  question  has  been  raised 
whether,  because  the  smaller  potatoes  are  usually  formed 
later  in  the  season,  the  practice  of  using  these  small 
potatoes  for  seed  would  tend  to  produce  a  late  strain. 
For  all  practical  purposes,  the  tendency  in  this  direc- 
tion, if  present  at  all,  would  be  so  slight  as  to  be  negli- 
gible. As  the  sprouts  come  only  from  the  neck  of  the 
potato  and  as  the  greater  number  of  smaller  potatoes 
contained  in  a  bushel  provides  a  much  larger  total  sur- 
face area  from  which  the  buds  may  grow  out,  it  is 
quite  evident  that  economy  would  result  from  the  use 
of  small  tubers  in  so  far  as  the  number  of  plants  pro- 
duced is  concerned.  This  fact  is  further  augmented  by 
the  difficulty  of  disposing  profitably  of  the  small  potatoes 
on  the  market  for  any  other  purpose  than  for  seed. 
Although  some  growers  maintain  that  more  vigorous 
plants  are  produced  from  the  larger  tubers,  more  sub- 
stantial evidence  will  have  to  be  secured  before  dis- 
continued use  of  the  small  tubers  is  warranted,  espe- 
cially if  they  are  chosen  from  high  yielding  hills.  It 
is  probable  that  certain  varieties  have  a  greater  tendency 
to  produce  stringy  potatoes  than  do  other  kinds  under 
the  same  conditions.  It  is  evident  that  in  case  of  a 
mechanical  mixture  of  two  such  varieties,  continued 
selection  of  the  small  tubers  would  result  in  the  in- 
ferior variety  becoming  dominant  over  the  more  de- 
sirable one.     As  has  been  stated,  however,  the  tubers 


60  llie  Sweet  Fotaio 

of  different  varieties  slioiild  never  be  mixed.  In  gen- 
eral, it  may  be  said  that  painstaking  hill  selection 
should  be  practiced  in  the  fall  at  digging-  time,  the  po- 
tatoes selected  being  carefnllj-  saved  in  a  storage-house 
and  culled  over  in  the  spring.  Medium-sized  or  small 
tubers  are  preferred. 

Production  of  seed  potatoes. 

Some  growers  have  adopted  a  systematic  method  of 
producing  their  seed  stock  with  a  view  to  the  elimina- 
tion of  disease,  improvement  in  quality  and  economy 
and  convenience  of  growth  without  going  through  the 
entire  field  each  year.  One  system  is  managed  on  the 
same  principle  as  the  "  ear-to-row "  test  in  seed-corn 
selection.  A  special  seed  patch  is  prepared.  Medium- 
sized  well-shaped  potatoes  are  selected  from  high  pro- 
ducing hills  and  enough  are  bedded  to  produce  slips 
for  the  seed  patch.  The  following  year  the  same  care- 
ful hill  selection  is  made  from  the  seed  patch  for  tubers 
to  bed  for  select  plants  the  next  year,  the  remainder  of 
the  seed-patch  potatoes,  whether  from  high  yielding 
hills  or  not,  being  used  to  bed  for  the  main  field  crop. 
This  practice  is  probably  justifiable  when  planting  is 
done  on  a  large  scale  and  when  wholesale  selection  of 
tubers  for  the  entire  field  crop  would  have  to  be  trusted 
in  the  hands  of  unreliable  farm  labor.  The  specialized 
production  of  seed  stock  from  vines  has  been  found  of 
value,  especially  in  the  control  of  disease  and  in  the 
better  keeping  quality  of  potatoes  produced  in  this 
way. 

Seed  treatment. 

Even  though  careful  culling  of  bruised  and  diseased 


Propagation 


61 


potatoes  has  been  practiced,  mncli  may  be  accomplished 

toward  preventing  trouble  in  the  seed-bed  by  dipping 

the    seed   from   five   to 

eight  minutes  in  a  solu- 
tion made  by  dissolving 

1     ounce    of    corrosive 

sublimate  in  8  gallons 

of    water.       (Fig.     6.) 

An  old  lard  or  molasses 

barrel     may     be     used 

conveniently     for     the 

solution    and    the    seed 

emersed    in     any    con- 
venient container  which 

will  permit  the  escape 

of  the  water  back  into 
the    barrel.     It    is    not 

necessary  that  the  seed 

be  rinsed  in  clean  water 
before  bedding.  After  treating  three  or  four  lots  of 
seed,  the  solution  should  be  discarded  or  more  corrosive 
sublimate  added.  This  treatment  is  designed  to  kill  the 
disease  spores  on  the  surface  rather  than  to  reach  those 
that  may  be  present  within  a  partly  decayed  tuber. 
Although  having  no  effect  on  stem-rot,  this  treatment 
is  helpful  in  controlling  black-rot  and  soft-rot,  if  the 
tubers  are  not  already  affected.  It  has  also  been  re- 
ported that  soft-rot  may  be  prevented  by  dipping  the 
seed  in  equal  parts  of  sulfur  and  air-slaked  lime.^ 

1  Report  of  the  conference  on  sweet  potato  problems  and  on 
diseases  of  cotton,  corn  and  tomatoes,  Birmingham,  Ala.,  Feb., 
1919. 


Figure  6. —  Dipping  sweet  po- 
tato seed  in  mercuric-chloride 
1:8  for  eight  minutes  just  before 
bedding. 


62  I'he  Sweet  Potato 

THE    ri-ANT-BED 

The  kind  of  plant-bed  to  be  used  will  depend  on  the 
area  to  be  planted,  climatic  conditions  and  the  facilities 
at  hand  for  its  preparation  and  operation.  The  grow- 
ers of  the  Atlantic  Coast  area  usually  provide  for  one 
large  sash  or  an  area  equal  to  about  32  square  feet  for 
each  bushel  of  potatoes  to  be  bedded.  From  15  to  20 
square  feet  of  surface  are  required  for  a  bushel  of 
medium-sized  tubers,  while  an  equal  amount  of  small 
roots  will  cover  25  to  30  square  feet  of  bed,  when  they 
are  placed  as  close  together  as  possible  without  touching. 

Location. 

The  first  and  one  of  'the  most  important  considera- 
tions demanded  by  the  plant-bed  is  its  location.  ]^o 
other  one  factor  is  so  important  as  the  choice  of  a  good 
site.  Especially  is  this  true  when  strong  plants  are 
desired  to  provide  the  early  crop.  A  high  well-drained 
spot  should  be  selected,  and  in  the  regions  north  of 
South  Carolina  a  windbreak  protecting  the  bed  on  the 
north  is  very  desirable.  In  any  case,  cold  windy  places 
should  be  avoided,  and  unobstructed  sunlight  is  essen- 
tial. The  southern  or  southeastern  slope  of  a  hill  or  a 
location  protected  on  the  north  and  northwest  by  thick 
woods  or  a  large  building  is  desirable.  Where  no  nat- 
ural protection  is  possible,  growers  often  provide  arti- 
ficial windbreaks  by  the  use  of  some  thickly  growing 
hedge  such  as  privet  or  arbor-vitae  thickly  planted.  In 
the  more  northern  areas,  a  tight  board  fence  is  some- 
times constructed  around  the  bed,  but  usually  when  only 
sweet  potatoes  are  grown,  protection  on  the  north  side 
is  sufficient. 


Propagation  63 

The  plant-bed  will  require  frequent  and  careful  at- 
tention and  should  be  so  situated  as  to  be  easily  ac- 
cessible at  all  times.  Proximity  to  the  field  is  not  so 
important  as  nearness  to  the  residence,  as  transporta- 
tion of  the  plants  is  comparatively  easy.  Many  large 
growers  have  found  it  convenient  to  provide  a  small 
shed  where  the  plants  may  be  placed  temporarily  in  the 
shade  while  waiting  to  be  carried  to  the  field  for  plant- 
ing. 

Convenient  watering  facilities  are  an  absolute  neces- 
sity and  this  should  be  borne  in  mind  when  selecting 
the  site.  If  the  home  place  is  located  on  a  hill  and  the 
plant-bed  is  on  lower  ground  nearby,  a  very  convenient 
and  economical  watering  system  can  often  be  provided 
by  piping  water  from  the  home  well  to  a  barrel  placed 
on  a  platform  at  the  bed.  When  such  a  system  is  used, 
the  water  is  convenient  both  for  watering  the  bed  and 
for  filling  the  planter  when  it  comes  for  a  supply  of 
plants.  An  open  trough  may  often  be  used  to  convey 
the  water  instead  of  pipe  when  the  former  is  more 
economical.  Thoughtful  care  in  locating  the  plant-bed 
will  be  repaid  many  times  in  profits  received. 

Preparation  of  the  plant-hed. 

The  proper  preparation  of  the  plant-bed  is  very  im- 
portant for  it  is  here  in  a  comparatively  small  space 
that  plants  are  to  be  produced  to  set  the  whole  or  a 
good  part  of  the  entire  acreage.  The  plant-bed  is  the 
medium  of  a  very  intensive  form  of  production.  If 
the  plants  do  not  receive  a  good  start  in  life,  their 
growth  will  be  greatly  hampered.  Therefore,  no  pains 
should  be  spared  in  preparing  the  plant-bed  in  the  most 
thorough  manner  consistent  with  economy.     The  kind 


64  The  Sweet  Potato 

of  seed-bed  to  be  used  and  the  manner  in  which  it  is  to 
be  prepared  will  be  goveraed  very  largely  by  prevailing 
climatic  conditions,  the  number  of  plants  to  be  produced 
and  peculiar  conditions  that  may  be  present  in  indi- 
vidual cases.  In  the  Gulf  states,  plants  are  either 
grown  in  the  open  or  in  coldframes,  while  a  little  far- 
ther north  hotbeds  are  employed  quite  extensivel^v. 
These  may  be  heated  with  decaying  manure,  a  coal  or 
wood  furnace  with  flues  running  under  the  beds  or 
with  a  hot-water  system. 

Open  beds. 

By  far  the  greater  number  of  sweet  potato  plants  in 
the  South  are  produced  in  open  beds.  Farmers  who 
grow  an  acre  or  two  for  home  use  and  who  bed  out  a 
few  bushels  of  seed  instead  of  ordering  their  plants 
from  a  dealer,  seldom  go  to.  the  trouble  to  provide  a 
permanent  plant-bed  of  any  kind.  Nor  would  they  be 
justified  in  so  doing  when  such  a  small  acreage  is  in- 
volved and  since  frequently  the  bed  would  be  used  for 
no  other  purpose  than  for  the  potatoes.  Even  when  a 
considerable  acreage  is  to  be  planted,  the  open  bed 
method  is  often  preferable  in  the  more  southern  areas. 
Because  of  the  longer  growing  period  in  this  section, 
extra  early  plants  are  not  always  desired,  consequently 
the  seed  may  not  be  bedded  until  late  when  the  gTound 
has  become  sufficiently  warm  to  make  bottom  heat  un- 
necessary. The  growing  of  plants  in  the  open  is  very 
widely  resorted  to  as  being  most  consistent  with  con- 
venience and  economy. 

The  open  bed  must  be  so  located  as  to  allow  thor- 
ough drainage.  Although  an  excavation  is  usually  de- 
sirable to  provide   room  for  the  extra  sand   that   is 


Propagation  65 

added  without  raising  the  level  of  the  bed  too  high 
above  that  of  the  surrounding  ground,  under  no  cir- 
cumstances should  the  bed  level  be  lower  than  the 
general  land  contour.  The  general  practice  is  to  make 
an  excavation  5  or  6  inches  deep,  5  or  6  feet  wide  and 
as  long  as  is  needed  for  the  quantity  of  potatoes  to  be 
bedded.  About  4  inches  of  clean  sand  is  placed  in  this 
excavation.  The  tubers  are  put  on  top  of  this  sand 
as  close  together  as  possibla  without  touching,  after 
which  they  are  covered  with  2  inches  of  sand.  This  bed 
is  kept  damp  by  sprinkling  daily  until  the  plants  appear. 
As  soon  as  the  young  shoots  may  be  seen,  another  inch 
of  sand  should  be  added  to  insure  the  development  of 
a  vigorous  root  system.  The  importan'ca  of  using  pure 
sand  in  the  seed-bed  cannot  be  over-emphasized.  The 
practice  sometimes  followed  of  placing  the  tubers  on 
top  of  a  thin  layer  of  manure  is  unjustified.  The 
sprouts  grow  from  material  stored  in  the  potatoes  and 
rich  soil  is  not  required.  'Npt  only  is  manure  unneces- 
sary (except  in  the  sub-layer  for  bottom  heat)  but  it  is 
a  carrier  of  disease.  Pure  sand  about  the  potatoes  is 
most  certain  to  produce  a  large  crop  of  strong,  healthy, 
well-rooted  plants.  Such  a  bed  may  be  covered  with 
straw,  hay  or  leaves  to  protect  it  from  cold  early  in  the 
season.  Old  burlap  sacks  are  also  sometimes  used  for 
this  purpose.  Such  coverings  may  be  valuable  in  pre- 
venting too  rapid  drying  out  of  the  surface. 

Coldframes. 

Some  of  the  largest  commercial  plant-growers  in  the 
South  and  Southwest  gi'ow  their  slips  in  glass  and  can- 
vas-covered coldframes.  When  potatoes  are  produced 
as  an  early  truck  crop,  some  means  of  protection  so 


66  The  Sweet  Potato 

as  to  allow  earlier  planting  is  necessary  even  in  the 
region  bordering  the  Gulf.  The  commercial  growers 
are  particularly  desirous  of  producing  early  plants 
which  bring  the  best  prices,  and  in  the  lower  South  the 
coldframe  answers  this  purpose.  The  location  of  the 
coldframe  should  be  considered  with  the  same  care  as 
for  an  open  bed;  Plate  II  shows  a  location  well 
protected  from  cold  winds  by  a  natural  forest  wind- 
break. 

Although  coldframes  may  be  constructed  entirely 
above  the  ground  or  only  partly  so,  the  former  method 
is  usually  employed  because  of  convenience  and  thor- 
ough drainage  which  is  afforded.  (See  Plate  I.)  Or- 
dinarily a  frame  is  made,  using  14-inch  boards  on  the 
north  or  west  side  and  8-  or  10-inch  boards  on  the 
south  or  east  side,  the  ends  being  boxed  up.  The  sides 
of  the  frame  are  held  rigidly  in  place  by  cleats  which 
are  spaced  at  intervals  of  about  6  feet,  the  side  boards 
being  nailed  to  these.  Brace-strips  of  1x4  or  2x4 
material  extend  from  one  side  to  the  other  at  every 
place  where  the  side  boards  are  nailed  to  the  cleats.  If 
the  bed  is  below  the  ground  surface,  the  frame  should, 
of  course,  be  made  to  fit  in  the  excavation.  When  built 
above  the  ground,  the  frame  is  hereby  nailed  together 
and  set  on  the  surface,  being  held  rigidly  tcf  the  ground 
by  means  of  the  cleats  above  mentioned  which  may  be 
extended  into  thc'  soil.  Further  protection  from  coid 
may  be  secured  by  banking  dirt  against  the.  north  side 
and  the  ends.  The  standard  width  for  either  a  cold- 
frame  or  hotbed  is  about  6  feet.  The  length  will  of 
course  be  determined  entirely  by  the  quantity  of  po- 
tatoes to  be  bedded.  The  coldframe  is  ordinarily  cov- 
ered   with    canvas    (Plate    I),    although    hotbed    sash 


Propagation  67 

are  sometimes  employed.  The  cross-brace  pieces  are 
more  conveniently  spaced  every  3  feet  if  sash  are  used. 
They  thereby  act  as  supports  for  the  sash  and  facilitate 
adjusting  the  ventilation. 

Clean  sand  is  used  in  the  coldframe  and  the  tubers 
are  bedded  just  as  in  the  open  bed  method. 

Hotbed, —  manure-heated. 

The  commercial  sweet  potato  crop  of  this  country  is 
very  largely  gi'own  from  plants  produced  in  hotbeds. 
This  is  because  the  states  of  New  Jersey,  Delaware, 
Maryland  and  Virginia,  which  at  this  time  grow  the 
greater  part  of  the  crop  put  on  the  market,  have  growing 
seasons  too  short  to  allow  the  plants  to  be  started  in 
coldframes;  because  of  the  increased  price  which  the 
early  crop  brings ;  and  the  possibility  of  growing  earlier 
plants  in  hotbeds  than  could  be  produced  otherwise. 
The  tubers  are  ordinarily  bedded  six  to  eight  weeks 
before  weather  conditions  permit  the  plants  to  be  set 
in  the  field.  In  bedding  so  early,  artificial  bottom- 
heat  is  necessary  to  overcome  outside  temperatures  and 
to  obtain  a  quick  growth  of  large  stocky  plants.  Fresh 
rapidly  fermenting  horse-manure,  which  is  naturally 
bulky  and  contains  a  large  amount  of  organic  matter 
capable  of  creating  considerable  heat  in  the  process  of 
decomposition,  furnishes  the  cheapest  and  simplest 
method  of  supplying  this  bottom-heat.  In  preparing  a 
hotbed,  the  frame  is  made  in  the  same  way  as  in  con- 
structing a  coldframe,  but  an  excavation  must  be  made 
for  the  manure.  The  depth  of  the  manure  will  be  in- 
fluenced by  the  severity  of  the  temperature  to  be  over- 
come and  the  length  of  time  heat  will  be  required.  The 
depth  usually  ranges  from  12  to  18  inches.     It  is  better 


68  The  Sweet  Potato 

to  have  the  hotbed  extend  east  and  west  as  the  sun-rays 
concentrated  bv  the  glass  will  be  of  substantial  value  in 
supplying-  heat.  Sash-bars  or  cross-rafters  to  slide  the 
sash  on  may  or  may  not  be  used ;  if  the  walls  are  prop- 
erly supported  at  the  comers  and  at  intervals  along  the 
sides  by  2  X  4  inch  stakes  driven  into  the  ground,  cross 
rafters  are  not  essential. 

A  layer  of  fresh  horse^manure  at  least  12  inches 
deep  is  placed  in  the  pit  a  week  before  bedding  the 
potatoes  and  thoroughly  packed  by  tramping.  Manure 
which  contains  old  sweet  potato  refuse  or  culls  from 
the  storage-house  should  be  carefully  avoided  as  dis- 
eases may  be  conveyed  in  this  manner.  Before  using, 
the  manure  should  be  piled  and  forked  over  two  or  three 
times  to  insure  uniformness  throughout.  In  case  the 
manure  is  dry,  it  should  be  watered,  as  moisture  is  an 
essential  to  the  decomposition  which  produces  heat.  A 
layer  of  clean  sand  3  or  4  inches  deep  is  spread  evenly 
over  the  manure  as  soon  as  heating  starts.  This  sand 
should  always  be  obtained  fresh  from  the  woods,  a  pit, 
or  some  place  where  it  has  had  no  chance  to  become 
infected  with  disease.  Some  of  the  most  serious  dis- 
eases develop  in  the  plant-bed  and  every  precaution 
should  be  taken  against  their  introduction.  Fresh 
sand  should  be  used  for  bedding  each  season,  as  disease 
may  remain  in  the  sand  and  carry  infection  over  until 
the  next  year.  The  woodwork  of  old  beds  should  be 
sprayed  each  year  as  a  precaution  against  disease. 

After  the  bed  has  been  prepared,  it  is  best  to  place 
the  sash  in  position  and  allow  the  heat  to  become  con- 
stant before  the  seed  are  bedded.  When  the  tempera- 
ture has  dropped  to  80  or  85  degrees  F.,  the  tubers  are 


Propagation  69 

placed  on  the  surface  and  covered  with  sand  as  has  al- 
ready been  explained. 

Hotbeds  which  are  to  be  pennanent  are  sometimes 
made  of  brick,  stone  or  concrete,  but  growers  generally 
prefer  the  cheap  practical  bed  just  described.  This 
can  be  used  for  a  few  years  and  when  demolished  by 
decay  the  expense  of  building  new  is  not  so  great  as  to 
offset  the  advantage  of  being  able  to  move  the  bed  at 
will. 

Hotbed, —  -flue-heated. 

In  the  more  northern  areas  and  where  it  is  difficult 
to  obtain  a  sufficient  quantity  of  the  proper  kind  of 
manure,  heat  for  the  hotbed  may  be  secured  from  a 
stove  or  furnace  through  conduction  pipes  under  the 
beds.  The  flue-heated  bed  may  be  constructed  for  one 
or  two  tiers  of  sash.  When  two  tiers  are  used,  they 
are  elevated  in  the  center  and  slope  to  each  side.  Hot- 
beds so  equipped  are  frequently  made  of  brick,  stone 
or  concrete  as  they  are  usually  intended  to  be  more  or 
less  permanent.-  However,  a  temporary  structure  may 
be  made  of  wood.  J.  C.  C.  Price,  ^  gives  the  following 
discussion  on  the  construction  of  a  flue-heated  hotbed; 
"  A  flue-heated  hot-bed  may  be  constructed  of  con- 
crete or  boards  for  sides.  The  first  is  permanent,  while 
the  boards  will  rot  out  after  a  period  of  time.  If  the 
boards  are  treated  with  creosote  they  will  last  much 
longer.  The  frame  should  be  located  on  a  well-drained 
place,  sloping  to  the  south  or  southeast,  so  as  to  get  the 
full  benefit  of  the  sun's  rays  and  be  protected  from 
north  and  north-west  winds.     When  possible,  the  frame 

1  Circ.  15,  Ala,  Exp.  Sta. 


70 


T/ie  Sweet  Potato 


is  placed  on  a  slight  slope  with  the  fire  box  at  the  lower 
end,  thus  giving  the  necessary  slope  to  the  floor. 

"  The  fire  box  is  constructed  of  brick  and  should  be 

arched.  The  di- 
mensions (as 
given  in  Fig.  7) 
are  18  inches 
wide  (inside 
m  e  a  s  u  r  ements  ) , 
20  inches  high, 
and  4  feet  and  8 
inched  long.  The 
terra  cotta  flue 
pipe  leading  un- 
der the  bed  is  8 
inches  in.  diame- 
ter and  should 
extend  the  entire 
length  of  the 
frame  into  the 
chimney  at  the 
other  end.  The 
first  two  or  three 
joints  of  the  flue 
should  be  covered 
with  brick,  as  the 
blaze  from  the 
fire  might  cause  it  to  become  too  hot  and  endanger  the 
floor.  The  chimney  may  be  made  of  brick  or  by  nailing 
together  four  12-inch  boards  in  box  fashion.  The  chim- 
ney should  be  larger  than  the  flue  under  the  floor  as  it 
will  draw  better. 


Figure    7. —  Showing   the    construction 
of  a  fire-heated  draw  bod. 


Propagation  71 

"  The  wooden  floor  should  be  built  at  least  four 
inches  above  the  flue,  so  as  not  to  catch  fire  and  to 
give  better  distribution  of  heat.  The  floor  should  have 
a  slope  of  one  inch  to  seven  and  one-half  feet,  or  twelve 
inches  in  ninety  feet.  That  is,  the  soil  at  the  furnace 
end  should  be  eighteen  inches  deep  and  at  the  chimney 
end  six  inches  deep.  The  flue  under  the  floor  should 
have  the  same  slope  as  the  floor.  The  soil  on  top  of  the 
frame  should  be  level.  Any  kind  of  rough  boards  may 
be  used  as  flooring.  They  should  be  treated  with  creo- 
sote to  make  them  more  durable. 

"  As  shown  in  the  drawing,  the  frame  should  slope 
toward  the  sun  and  should  be  six  inches  higher  on  the 
back  than  on  the  front  side.  The  top  of  the  frame 
should  be  level  from  east  to  west." 

Hotbed, —  pipe-heated. 

A  type  of  hotbed  rapidly  gaining  in  favor  among  the 
commercial  plant-growers  of  the  northern  areas  is  one 
heated  by  means  of  hot  water  or  steam  pipe  lines,  which 
may  be  supplied  from  a  greenhouse  boiler  or  a  separate 
heating  furnace.  The  lines  of  pipe  are  commonly  laid 
4  or  5  inches  below  the  bed  surface.  Miller  ^  describes 
the  method  as  follows :  "  Where  a  steam  or  hot -water 
boiler  is  used  for  heating  a  greenhouse,  residence  or 
other  structure,  it  can  often  be  employed  to  good  ad- 
vantage in  heating  the  sweet  potato  bed.  In  fact,  where 
sweet  potato  plants  are  groMoi  on  a  very  large  scale  it 
might  be  advisable  to  install  hot  water  or  steam  heat 
even  if  it  is  not  used  for  other  purposes.  The  tem- 
perature of  the  bed  can  be  regulated  more  easily  where 
1  Farmers'  Bull.  999,  U.  S.  Dept.  Agr.,  page  11. 


72  The  Sweet  Potato 

steam  or  hot  water  is  employed  than  where  other  meth- 
ods of  supplying  heat  arc  nsed. 

"  When  steam  or  hot-water  pipes  are  nsed  to  heat 
the  hotbed,  the  best  results  are  secured  when  the  pipes 
are  placed  near  the  bottom  of  the  hotbed  pit,  the  soil 
being  put  on  a  tile  or  board  floor  resting  on  pipe  or 
wooden  supports  so  as  to  leave  a  space  of  a  few  inches 
between  the  bottom  of  the  pit  and  the  floor.  The  num- 
ber and  size  of  the  heating  pipes  required  depend  on 
the  rapidity  of  the  circulation  and  on  the  temperature 
of  the  water  or  the  pressure  of  the  steam.  When  hot 
water  is  used,  four  11/^-inch  pipes  will  be  ample  in 
most  cases  for  beds  not  over  50  feet  long.  For  larger 
beds  2-inch  pipes  should  be  used.  Two  of  the  pipes 
serve  as  flow  pipes  and  two  as  returns.  The  water 
enters  at  one  end,  makes  the  circuit  of  the  bed,  and 
leaves  at  the  same  end.  The  point  where  the  pipes 
enter  the  bed  should  be  the  highest  in  the  system,  and 
the  point  where  the  pipes  leave  the  bed  the  lowest  in  the 
system.  The  pipes  should  have  a  uniform  grade  and 
should  be  evenly  spaced,  with  the  flow  pipes  about  a 
foot  from  each  outside  wall  and  the  returns  in  the 
middle.  When  steam  is  employed  the  arrangement  of 
the  bed  and  pipes  is  the  same,  but  smaller  pipes  may  be 
used.  With  steam  at  10  pounds  pressure  1-inch  pipes 
are  large  enough  for  50-foot  beds,  and  l^^'inch  pipes 
are  ample  for  beds  up  to  100  feet  long." 

A  general  idea  of  the  construction  of  a  pipe-heated 
bed  may  be  gained  from  Fig.  7.  The  same  rules  gov- 
erning greenhouse  heating  apply  to  piping  beds  of  this 
kind. 


Propagation  73 

Other  types  of  Jiotheds. 

In  the  absence  of  stable  manure  and  when  the  size 
of  the  bed  is  not  enough  to  justif}^  the  installation  of 
one  of  the  more  elaborate  heating  systems  just  dis- 
cussed, other  simpler  heat-producing  materials  may  be 
employed.  A  moderate  hotbed  may  be  heated  by  means 
of  oak  leaves,  damp  with  fresh  lime  sprinkled  through 
them  as  they  are  packed  in  the  excavation  (which  should 
be  at  least  2  feet  deep)  under  the  frame.  Such  beds 
will  produce  moderate  heat  and  will  hold  it  longer  than 
stable  manure.  An  ordinary  cotton  cloth  may  be  used 
for  a  cover.  ]\fany  growers  use  no  cloth  or  glass,  but 
often  cover  thickly  with  pine  straw,  raking  it  off  on 
warm  sunny  days  and  covering  again  at  night.  Pine 
straw  and  mold  have  been  used  for  bottom-heat  but 
they  are  of  practically  no  value. 

Bedding. 

In  regions  as  far  north  as  l^ew  Jersey  and  New  York, 
bedding  is  not  ordinarily  done  before  April  1st  to  10th, 
while  in  the  lower  South  the  seed  may  be  bedded  in 
early  ]\Iarch.  A  bed  100  feet  long  and  6  feet  wide 
should  furnish  enough  plants  to  set  six  acres  at  the 
first  drawing  and  enough  for  three  acres  more  ten  days 
later.  It  will  require  about  35  bushels  of  average  seed 
for  a  bed  this  size.  The  sand  in  the  bed  should  be  at  a 
temperature  of  about  85  degrees  F.  at  the  time  of  bed- 
ding, and  should  be  allowed  to  drop  slowly  to  70  degrees 
F.  A  minimum  temperature  of  60  degrees  F.  should 
be  maintained  during  the  entire  bedding  season.  The 
seed  should  be  handled  carefully  and  not  allowed  to 


74  The  Sweet  Potato 

chill  in  moving  from  storage  to  the  newlv  prepared  bed. 
For  convenience,  burlap-lined  baskets  should  be  used 
and  bedding  is  preferably  done  on  a  warm  bright  day. 
The  seed  should  be  carefully  examined  for  disease  and 
all  suspicious  tubers  discarded.  All  the  seed  should 
receive  the  corrosive  sublimate  treatment  already  de- 
scribed. (Page  61.)  After  draining,  the  tubers  are 
carefully  laid  by  hand  as  closely  together  on  the  bed 
surface  as  possible  without  having  them  touch.  (Plate 
I.)  If  the  potatoes  are  crowded  in  the  bed,  dis- 
ease may  be  spread  from  one  tuber  to  another  and  the 
sprouts  will  be  so  crowded  that  long  spindling  plants 
will  be  produced.  If  unusually  large  roots  are  em- 
ployed for  seed,  they  may  be  split  lengthwise  and  placed 
with  the  cut  side  down  in  the  bed.  Many  growers  have 
found  that  a  thin  layer  of  pine  needles  placed  over  the 
potatoes  before  the  sand  is  applied  aids  materially  in 
holding  the  tubers  in  place  when  the  plants  are  pulled. 
Only  part  of  the  top  sand  should  be  applied  when 
bedded,  for  if  the  tubers  are  covered  too  deeply  some 
rotting  may  result.  Ordinarily  about  2  inches  of  sand 
is  applied  when  bedded  and  an  additional  inch  put  on 
after  the  shoots  appear.  The  covering  sand  should  be 
evenly  distributed,  carefully  smoothed  and  lightly 
packed  by  planking.  Only  clean  fresh  sand  should  bo 
employed.  As  has  been  stated,  sand  is  as  good  as  rich 
soil  for  the  sprouts  come  from  the  material  stored  in 
the  potato.  Ilowever,  the  use  of  sawdust  should  be 
avoided.  After  the  bed  has  been  completed,  it  should 
at  once  be  wet  thoroughly  with  a  fine  spray  from  the 
hose  or  with  a  sprinkling-can. 


Propagation  75 

Covering  for  seed-heds. 

Some  kind  of  covering,  if  not  always  essential,  is 
desirable  for  the  protection  of  the  young  plants  from 
cold  nights  and  from  the  cool  temperatures  that  often 
occur  late  in  the  season. 

With  a  moderate  hotbed,  sweet  potato  plants  can  be 
grown  under  cloth  as  well  as  glass.  Many  growers, 
from  South  Carolina  and  Tennessee  southward,  use  no 
other  cover  than  pine  straw,  which  is  raked  off  in  the 
daytime  after  the  plants  are  started  and  replaced  at 
night.  If  the  nights  are  cool,  pine  straw  is  frequently 
employed  to  cover  the  beds  before  the  plants  appear. 

The  ordinary  liotbed  frame  may  be  covered  witli  cot- 
ton twilled  cloth.  The  kind  of  covering  may  materially 
influence  the  type  of  seed-bed  to  be  employed.  In  re- 
gions south  of  North  Carolina,  light  bottom-heat  is  often 
needed  when  a  cloth  covering  is  used,  while  in  the  same 
territory  no  bottom-heat  may  be  required  if  glass  sash 
is  employed  and  properly  managed.  When  cotton  cloth 
is  used,  it  should  be  treated  with  hot  linseed  oil  to  ren- 
der it  waterproof  and  to  lengthen  its  usefulness  by  pre- 
venting decay.  Canvas  covers  should  be  tacked  on  one 
side  and  provided  with  poles  on  which  they  can  be  rolled 
up  in  the  daytime  to  admit  sunlight  and  secure  ventila- 
tion. Handling  the  cloth  cover  will  be  greatly  facili- 
tated by  providing  support  lathes  or  wires  at  frequent 
intervals.  Such  construction  will  cause  the  water  to 
drain  off  without  forming  puddles  and  dripping  on  the 
bed.  In  Texas,  Oklahoma  and  Louisiana,  commercial 
plant-gTowers  frequently  use  coldframes,  6  feet  wide, 
constructed  of  8-inch  strips  for  the  sides.  A  thin  cotton 
cloth  is  merely  tacked  over  this  flat  bed  and  only  re- 


76  21ie  Siveet  Potato 

moved  about  once  a  week,  the  watering  being  done  by 
sprinkling  on  top  of  the  cloth.  These  coverings  are  so 
thin  that  considerable  sunlight  is  given  the  plants  with- 
out moving  the  cover.  In  these  warm  sections,  this 
practice  seems  satisfactory  although  the  cloth  covers 
seldom  last  more  than  one  season.  If  good  canvas  is 
used  and  properly  oiled  and  cared  for,  it  may  last  sev- 
eral years  and  makes  a  suitable  covering  even  for  the 
hotbeds  as  far  north  as  Virginia. 

Glazed  hotbed  sash  are  more  commonly  used  as  cover- 
ings in  the  northern  part  of  the  sweet  potato  district, 
for  both  manure  and  fire-heated  beds.  The  regular 
3X6  foot  sash  is  commonly  employed.  A  cheap  home- 
made sash  is  sometimes  built  by  the  use  of  scrap  glass 
and  suitable  strips  of  lumber.  Johnson  and  Kosa  ^  de- 
scribe these  home-made  sash  as  having,  "  six  rows  of 
small  panes  of  glass,  supported  on  wide  strips.  These 
obstruct  a  large  part  of  the  light,  which,  however,  is  not 
a  serious  objection  with  sweet  potatoes.  These  sash  are 
cheap  and  if  well  made  answer  the  purpose."  Sash, 
when  used,  should  slope  toward  the  south  or  east,  if  the 
greatest  benefit  is  to  be  derived  from  the  sunlight.  If 
carefully  handled  to  avoid  breakage  and  the  wooden  parts 
are  painted  each  year,  hotbed  sash  will  last  for  many 
seasons  and  will  in  the  end  prove  to  be  cheaper  than 
cloth  coverings.  As  they  are  always  useful  in  any  gar- 
den for  producing  all  kinds  of  young  plants  early  in  the 
season,  sash  are  perhaps  the  most  popular  among  grow- 
ers for  the  sweet  potato  plant-bed. 

A  board  covering  is  sometimes  used  but  because  of  the 
difficulty  involved  in  handling  and  its  inability  to  admit 
sunlight,  it  is  undesirable. 

1  Bull.  19,  Va.  Truck  Exp.  Sta.,  page  396. 


Fropagulion  77 

Care  of  the  plant-hed. 

When  the  plant-bed  has  been  placed  in  an  ideal  loca- 
tion, the  bottom-heat  perfectly  regulated,  the  top  soil  or 
sand  carefully  selected  and  applied  for  its  purity  and 
freedom  from  disease,  and  the  tubers  which  have  been 
carefully  selected  and  treated  for  disease  are  evenly 
placed  in  the  bed  and  covered,  the  task  of  producing 
strong  vigorous  plants  which  will  vitally  influence  the 
crop  yield  is  only  half  accomplished.  A  sweet  potato 
plant-bed  may  be  perfectly  prepared  but  unless  properly 
cared  for  discouraging  results  will  be  the'  consequence. 

Maintaining  temperature. —  As  has  been  stated,  the 
temperature  of  the  plant-bed  should  be  between  80  and 
90  degrees  F.  or  around  85  degrees  F.  when  the  tubers 
are  bedded.  This  heat  should  be  allowed  to  decrease 
gradually  until  a  constant  uniform  temperature  of  TO  to 
75  degrees  is  reached  at  the  end  of  about  six  weeks.  In 
no  case  should  the  temperature  be  allowed  to  go  below 
60  degrees  F.  as  it  is  sure  to  cause  injury  to  the  growing 
shoots.  The  temperature  of  the  bed  should  be  noticed 
carefully  every  day  for  the  first  ten  days.  A  ther- 
mometer should  be  kept  continually  in  the  soil.  In 
these  first  few  days  a  manure-heated  bed  may  suffer 
considerable  variation  in  temperature  which  will  re- 
quire regulating.  In  case  the  bed  is  not  well  drained, 
excess  water  may  find  its  way  into  the  manure,  destroy- 
ing the  heat  altogether  or  starting  a  new  fermentation 
resulting  in  the  production  of  heat  too  intense  for  the 
well-being  of  the  young  sprouting  buds.  In  case  of 
extreme  heat,  enough  water  should  be  applied  thor- 
oughly to  wet  the  surface  sand.  A  double  row  of  3- 
inch  holes,  1  foot  apart,  should  then  be  worked  along 


78  The  Sweet  Potato 

the  center  of  the  bed  through  to  the  manure.  This  may 
be  done  by  using  a  crowbar  which  is  pushed  into  the 
ground  and  then  removed.  Such  an  operation,  aided  by 
the  removal  of  any  covering,  will  rapidly  lower  the  tem- 
perature of  the  bed.  It  nearly  always  happens  that 
after  a  few  days  some  parts  of  the  bed  will  become  too 
hot  and  other  parts  too  cold.  The  cooler  places  should 
have  the  sash  left  over  them  during  the  heat  of  the  day 
so  that  the  sun's  rays  may  be  concentrated  on  them  while 
the  hotter  places  may  be  shaded.  Even  though  a  ther- 
mometer is  not  used,  an  experienced  grower  carefully 
examines  all  parts  of  the  beds  every  day  by  thrusting 
his  finger  into  the  sand  between  the  potatoes  and  below 
their  level.  If  a  comfortably  warm  temperature  can 
be  maintained  at  this  point,  it  is  satisfactory. 

Watering. —  Water  should  be  applied  abundantly  as 
soon  as  the  potatoes  are  bedded.  After  this  the  bed 
should  be  liberally  watered  two  or  three  times  each  week 
until  the  plants  begin  to  form  leaves.  After  the  leaves 
form,  the  bed  will  need  water  every  day.  It  is  best  to 
water  the  bed  about  three  or  four  o'clock  in  the  after- 
noon so  that  the  surface  of  the  soil  and  leaves  will  dry 
off  before  night.  If  this  is  done,  no  trouble  will  be  ex- 
perienced from  the  damping-off  fungi.  The  method  of 
heating  will  in  a  measure  influence  the  amount  of  water 
necessary.  A  steam-  or  furnace-heated  hotbed  will  re- 
quire more  water  than  will  an  ordinary  manure-heated 
bed.  Water  should  always  be  applied  in  a  spray  rather 
than  in  a  solid  stream.  This  may  be  accomplished  by 
means  of  a  sprinkling-can,  with  the  spray-nozzle  on  the 
hose  or  by  means  of  regulating  the  spray  with  the  hand 
as  it  comes  from  the  hose  without  any  nozzle.  Many 
growers  prefer  regulating  the  water  in  the  latter  way, 


Propagation  79 

claiming  they  can  better  place  it  where  desired.  Small 
growers  who  have  seed-beds  in  the  garden  sometimes 
prefer  to  use  lukewarm  water  containing  soap-suds  on 
their  plants.  The  wash-water  from  the  house  is  com- 
monly saved  for  this  purpose.  The  merit  of  this  prac- 
tice seems  to  be  questionable.  At  all  events,  it  is  im- 
practicable and  undesirable  for  the  planter  with  more 
extensive  beds.  Ordinarily  the  beds  may  be  allowed 
to  take  all  rains. 

liardening-off. —  It  is  recommended  that  the  sprouts 
be  allowed  to  reach  a  height  of  4  to  5  inches  above  the 
surface  of  the  sand  before  they  are  removed.  A  "  hard- 
ening-off  "  process  lasting  a  week  or  more,  during  which 
the  ventilation  is  increased  and  the  water  supply  shut 
off,  should  be  employed  before  transplanting.  This 
process  must  be  brought  on  gradually  as  the  time  for 
drawing  approaches.  Toward  the  end  of  the  period  in 
which  the  plants  are  to  remain  in  the  bed,  the  ventila- 
tion should  be  increased  by  leaving  off  the  cover  entirely 
during  the  warm  part  of  the  day  and  even  in  the  early 
morning  and  late  evening  considerable  more  ventilation 
can  be  given.  When  removed  entirely,  which  is  advis- 
able during  the  last  few  days  before  the  plants  are 
pulled,  the  cover  should  be  kept  close  at  hand  where  it 
can  be  put  on  quickly  in  case  of  a  late  cold  spell. 
Sweet  potatoes  are  very  sensitive  to  frost  and  even 
though  they  have  been  accustomed  to  the  air,  the  slight- 
est frosting  will  cause  serious  injury. 

Treatment  of  seed-bed  for  disease. —  Disease  may 
often  appear  in  the  plant-bed  after  the  tubers  have  been 
bedded,  especially  if  they  have  not  received  the  cor- 
rosive sublimate  treatment  already  discussed.  W.  F. 
Massey  recommends  spraying  the  bed  with  bordeaux 


80  The  Sweet  Potato 

mixture  in  such  cases,  for  the  purpose  of  killing  some  of 
the  causal  fungi  which  may  be  present.  However,  pre- 
vention is  far  easier  and  more  reliable. 

DEAWING    THE    PLANTS 

Sweet  potato  plants  should  not  be  set  in  the  field 
until  after  all  danger  of  frost  is  past.  The  plants  will 
ordinarily  be  ready  for  drawing  five  weeks  after  the  hot- 
bed has  been  put  down,  although  seven  or  eight  weeks 
are  sometimes  required  for  plants  to  reach  proper  devel- 
opment in  a  coldframe  or  open  bed.  The  ground  for 
planting  should  be  ready  and  the  plants  promptly  pulled 
when  they  are  5  to  6  inches  high.  The  common  prac- 
tice of  waiting  for  a  rain  to  transplant  is  unnecessary  if 
one-half  pint  of  water  is  applied  to  each  plant  when  set. 
In  fact,  many  growers  claim  the  plants  grow  off  better 
when  set  in  this  way. 

The  plants  should  be  drawn  carefully  one  at  a  time. 
If  the  roots  of  several  plants  are  grown  together,  they 
should  be  separated  at  the  bed  to  avoid  delay  in  the 
field.  Drawing  should  be  done  by  giving  the  plant  a 
sidewise  pull  with  the  right  hand  while  the  left  hand  is 
employed  in  holding  the  ground  firmly  to  prevent  the 
mother  potato  from  being  disturbed  or  drawn  up.  As 
the  plants  are  pulled,  they  should  be  placed  in  baskets  or 
crates  and  covered  with  a  burlap  sack  or  with  hay  to 
prevent  drying  out  while  being  carried  to  the  field.  It 
will  often  be  convenient  to  have  a  small  shed  at  the  bed 
in  which  the  plants  may  be  stored  with  roots  down  until 
needed  in  the  field.  ]\Iany  commercial  plant-growers 
have  a  special  shed  for  this  purpose  which  is  provided 
with  a  shallow  pit  in  which  the  bundles  of  plants  (100 
or  200  in  a  bundle)  may  be  stacked  with  the  roots  in 


Propagation  81 

soft  damp  soil  or  a  bed  of  saturated  moss  until  they  can 
be  packed  and  shipped  out.  The  plants  do  not  develop 
uniformly,  and  in  pulling  many  small  plants  must  be 
left  for  further  growth.  A  well-developed  root  system 
is  very  desirable  and  if  the  bed  has  been  properly  pre- 
pared with  sand  no  difficulty  will  be  experienced  in  this 
regard.  Much  time  may  be  saved  in  the  field  if  the 
plants  are  orderly  and  systematically  handled  at  the 
plant-bed.  All  roots  should  be  turned  in  the  same  direc- 
tion and  if  a  machine  is  used  for  transplanting,  it  will 
often  be  necessary  to  trim  off  long  or  irregular  tops  with 
a  knife.  It  is  essential  that  draws  planted  by  machine 
be  in  the  best  possible  condition  if  they  are  to  be  effi- 
ciently handled  by  the  boys  who  sit  on  the  back  and  feed 
the  plants  into  the  machine.  Nimbleness  is  necessary 
under  the  best  of  conditions  and  if  the  plants  are  ir- 
regularly arranged  and  grovm  together,  many  skips 
in  the  field  will  be  the  result. 

In  very  dry  weather  or  when  a  small  area  is  to  be  set 
by  hand-dropping  the  plants,  growers  sometimes  have  at 
hand  a  large  tub  containing  a  mixture  of  an  equal  part 
of  clay  and  cow-manure  mixed  to  the  consistency  of  a 
thin  slime  wdth  water.  As  the  plants  are  pulled  from 
the  bed,  they  may  be  taken  in  small  bunches  and  their 
roots  dipped  into  this  mixture.  This  "  puddling  "  pro- 
cess, though  of  some  value,  is  now  seldom  used  because 
of  the  disagreeable  feature  of  handling  the  plants  with 
mud-covered  roots.  The  plants  should  never  be  allowed 
to  stand  in  such  a  mixture  for  any  length  of  time,  as 
they  will  shed  their  leaves. 

In  preparing  plants  for  shipment,  commercial  grow- 
ers usually  tie  them  in  bundles  of  200  each  with  soft 
cotton  twine.     Perhaps  the  most  economical  method  of 


82  The  Sweet  Potato 

packing  is  in  a  burlap  bag  which  has  been  split  open  and 
cut  in  half  or  for  large  bundles  left  whole.  The  sack  is 
first  split  and  laid  on  the  ground  or  packing-table,  placing 
on  it  an  old  newspaper  which  has  been  dampened  with 
water.  The  bundles  of  plants  are  then  placed  roots 
down  on  top  of  the  wet  paper,  putting  them  in  a  circle 
with  a  bundle  in  the  center.  A  second  and  even  a  third 
layer  of  bundles  of  plants  may  be  placed  on  top  of  the 
first.  Each  succeeding  layer  should  contain  fewer  bun- 
dles than  the  first,  thus  building  the  pile  up  into  a  com- 
pact cone-shape.  The  package  is  tied  by  bringing  the 
corners  of  the  sack  together  in  the  center,  much  as  a 
bundle  of  clothes  would  be  tied  in  a  sheet.  Although 
the  roots  need  moisture,  the  tops  had  best  be  kept  dry. 
When  packed  in  crates  or  baskets,  damp  moss  is  fre- 
quently placed  around  the  roots.  From  2000  to  4000 
plants  can  ordinarily  be  packed  in  an  average  size  bur- 
lap bag  which  has  been  split  open  and  the  plants  ar- 
ranged as  described  above.  When  in  crates  or  baskets, 
the  plants  are  perhaps  not  bruised  so  much  as  when 
packed  in  burlap. 

USE    OF    VINE-CUTTINGS 

The  value  of  vine-cuttings  in  the  control  of  certain 
diseases  is  now  universally  recognized  throughout  the 
sweet  potato  area.  When  vines  are  cut  from  the  grow- 
ing plants  and  transplanted  in  new  fields  free  of  disease, 
the  potatoes  produced  will  be  disease-free.  Practical 
growers  have  long  since  discovered  the  value  of  this 
means  of  propagation  in  the  eradication  of  black-rot. 
For  this  reason,  vines  or  "  vine-cuttings  "  are  widely 
used  in  producing  tubers  which  are  to  be  employed  for 


Propagation  83 

seed.  Most  sweet  potato  authorities  now  advocate  grow- 
ing seed  from  vine-cuttings.  The  potatoes  grown  from 
vines  are  not  only  practically  free  from  disease  but  they 
seem  to  keep  better  in  storage  and  are  about  the  proper 
size  for  seed.  Frequently  the  main  crop  is  grown  from 
vine-cuttings,  only  enough  sets  being  planted  to  pro- 
duce vines  sufficient  to  set  the  required  acreage.  This 
practice  is  not  only  satisfactory  in-so-far  as  disease  con- 
trol is  concerned,  but  is  more  economical  than  purchas- 
ing or  raising  enough  plants  for  the  entire  acreage. 
When  a  machine  is  employed  for  setting  such  plants, 
all  or  most  of  the  leaves  must  be  stripped  from  the  cut- 
tings to  facilitate  handling.  The  cuttings  are  made  as 
soon  as  the  vines  are  3  or  4  feet  long.  Pieces  7  or  8 
inches  long  containing  about  two  joints  are  commonly 
used.  These  cuttings  are  usually  made  from  the  early 
vines  grown  from  slips.  Setting  and  handling  is  done 
the  same  as  with  slips.  It  is  generally  conceded  by 
growers  that  after  the  vines  have  begun  to  run  well,  the 
use  of  vine-cuttings  is  much  to  be  preferred  to  the  slips, 
especially  for  the  late  crop.  ITowever,  except  for  the 
advantages  already  mentioned,  experiments  have  shown 
practically  no  difference  in  yield.  It  has  been  found 
that  too  close  pruning  of  the  vines  will  decrease  the 
yield  of  marketable  potatoes  by  increasing  the  percent- 
age of  smaller  ones.  ^ 

The  effect  of  constant  propagation  by  vine-cuttings 
and  the  influence  on  yield  of  constant  selection  of  cut- 
tings from  plants  with  the  most  vigorously  growing 
vines  are  problems  yet  undetermined.  Individual 
plants  of  the  same  variety  growing  side  by  side  often 

1  G.  W.  Carver,  Bull.  30,  p.  7,  Tuskegee  Normal  and  Ind.  Inst. 


84  The  Sweet  rotato 

show  wide  variation  in  hardiness,  thrift  and  vigorous- 
ness  of  growth.  It  would  seem  reasonable  to  believe 
that  continued  selection  of  vine-cuttings  from  the  best 
individual  plants  would  in  time  give  favorable  results  in 
the  offspring.  Vine-cuttings  seem  to  be  especially  pop- 
ular for  the  very  late  crop.  Fitz  ^  cites  a  Georgia 
planter  who  with  vine-cuttings  planted  July  18,  which 
were  given  one  hoeing  and  one  plowing,  produced  a  yield 
of  125  bushels  to  the  acre,  more  than  half  of  which  were 
marketable  potatoes. 

When  planted  especially  for  the  production  of  seed 
potatoes,  the  vines  are  usually  not  set  until  July  or  the 
first  of  August.  This  late  planting  gives  a  good  yield 
of  small  tubers  which  are  easier  to  keep  than  potatoes 
from  the  earlier  plants.  It  is  preferable  to  plant  out 
vine-cuttings  just  after  a  rain  while  the  soil  is  wet,  but 
if  enough  water  is  used  they  may  be  planted  in  dry 
weather  about  as  successfully  as  draws  under  the  same 
conditions. 

E.  A.  Miller  ^  has  given  the  following  directions  for 
storing  sweet  potato  vines  which  he  says  has  been 
used  quite  successfully  in  some  western  sections: 
"  Take  four  boards,  about  eight  inches  wide,  drill  them 
full  of  holes  and  then  nail  them  together  to  form  a  hol- 
low flue.  8et  these  up  endwise  in  some  protectetl  place 
in  such  a  manner  as  to  form  a  flue,  and  then  place  the 
sweet  potato  vines  around  this  flue,  cover  with  straw  and 
bank  up  around  it  with  earth,  to  protect  them  from  cold. 
The  flue  will  permit  a  free  circulation  of  air  which  will 
keep  the  vines  alive  through  the  winter." 

1  Jas.  Fitz,  "  Sweet  Potato  Culture,"  page  73. 
-  Formerly  specialist  in  potato  storage  of  the  Extension  Service, 
Tex.  A.  &  M.  Coll. 


Propagation  85 

THE    COMMERCIAL    PLANT    BUSINESS 

In  recent  years  there  has  been  a  large  demand  for 
sweet  potato  phints  of  pure  varieties  which  are  free  from 
disease.  The  greater  part  of  the  sweet  potato  crop  in 
the  South  is  raised  by  small  faraiers  who  produce  just 
enough  for  home  use  and  possibly  a  few  to  sell  on  the 
local  markets.  These  growers  usually  prefer  to  buy  a 
new  supply  of  seed  or  plants  each  year  for  their  small 
area.  Recently  a  number  of  large  sweet  potato  storage 
companies  have  been  formed  for  the  purpose  of  produc- 
ing, buying  and  storing  the  crop.  These  organizations 
require  large  supplies  of  plants  to  set  their  new  area. 
These  conditions  and  the  continually  increasing  interest 
which  has  been  taken  in  sweet  potato  production  in  re- 
cent years  have  given  rise  to  the  development  of  a  num- 
ber of  commercial  plant  industries. 

Two  months  will  cover  the  time  required  to  produce 
salable  plants  from  seed.  As  a  bushel  of  seed  which 
can  ordinarily  be  bought  for  $2,00  or  less  will  produce 
from  2,000  to  4,000  plants  worth  as  much  a  thousand 
as  the  original  bushel  of  seed  cost,  there  is  opportunity 
to  realize  a  good  margin  of  profit  in  a  comparatively 
short  time  if  proper  care  is  exercised.  Often  heavy 
rains  will  prevent  the  beds  from  "  slipping  "  just  at  the 
season  when  the  plants  are  most  in  demand,  while  later 
on  an  abundance  of  plants  may  be  produced  which  can- 
not be  disposed  of  on  the  later  market.  However,  since 
some  growers  bed  10,000  bushels  or  more  seed,  assuming 
the  risk  of  their  disposal,  it  is  evidence  that  the  business 
can  be  made  to  pay  if  properly  handled  and  unfortunate 
occurrences  do  not  interfere. 


86  The  Sweet  Potato 

Field  methods. 

The  commercial  plant-grower  ordinarily  employs 
either  coldframes  or  fine-heated  or  pipe-heated  hotbeds, 
the  former  in  the  southern  and  southwestern  areas  and 
the  latter  farther  north.  Cloth  covers  are  used  on  the 
coldframes  commonly  and  the  beds  are  prepared  as  de- 
scribed for  ordinary  coldframes.  (See  page  66.)  An 
adequate  supply  of  water  must  be  provided  by  piping 
and  hose  connections,  by  running  one  or  two  pipes 
through  the  area  covered  by  beds  on  which  are  numerous 
faucets  for  hose  attachment.  JMen  must  be  kept  busy 
continually,  providing  for  the  proper  moisture  require- 
ments of  the  beds. 

Drawing  of  the  slips  is  done  by  negro  women  and 
girls  who  may  be  employed  at  a  relatively  low  figure 
and  can  accomplish  work  satisfactorily.  The  slips  are 
pulled  and  placed  in  piles,  200  plants  to  each  pile.  One 
or  more  of  the  hands  is  kept  busy  tying  these  bundles 
and  putting  them  into  containers  to  be  transported  to 
the  packing-shed.  A  superintendent  is  necessary  to  see 
that  the  drawing  is  done  carefully  and  that  the  counting 
is  correct.  At  the  packing-shed  the  plants  are  received 
by  the  packer  in  charge  who  stacks  them  roots  down  and 
one  layer  deep  in  a  shallow  pit,  the  bottom  of  which  is 
covered  with  damp  moss,  the  different  varieties  of 
course  being  kept  separate.  The  packer  will  find  it  con- 
venient to  work  on  a  low  platform  on  which  the  plants 
are  packed  in  sacks,  crates  or  boxes.  To  his  right  and 
above  the  packing  platform  is  a  roughly  constructed 
board  desk  on  which  is  kept  in  plain  view  the  order- 
sheet,  the  corresponding  shipping  tags  and  miscellan- 
eous supplies.     Hanging  over  the  packing  platform  is  a 


/  0 


Plate  IV. —  Varieties  of  sweet  potatoes.  Top :  Typical  speci- 
mens of  some  of  tlie  commercial  moist-fleshed  varieties  of  sweet 
potatoes:  a,  Yellow  Belmont:  b,  Pumpkin;  c,  Porto  Rico;  d.  Nancy 
Hall;  e,  Southern  Queen;  /,  Dooley;  g.  Bunch.  Bottom:  Some  of 
the  important  commorcial  dry-floslied  varieties  of  sweet  potatoes: 
a.  Big  Stem  Jersey;  h,  Triumph;  c,  Yellow  Jersey;  d.  Yellow  Jersey; 
e.  Red  Jersey.  Note  the  two  distinct  types  of  the  Yellow  Jersey 
variety. 


Propagation  87 

roll  of  soft  cotton  twine  which  is  used  for  tying  the 
plants  and  for  tagging.  This  twine  can  be  purchased  in 
rolls  of  about  fifty  pounds  each  which  are  so  made  that 
they  can  be  suspended  on  a  stick  placed  through  the  cen- 
ter and  unrolled  as  needed.  The  order-sheet  is  made 
out  at  the  office  by  the  owner  or  his  bookkeeper.  This 
sheet  includes  the  purchaser's  name  and  address  and  the 
variety  and  number  of  plants  desired.  Shipping  tags 
are  made  out  to  correspond  to  each  order  and  sent  down 
with  them  by  the  bookkeeper.  N^o  bookkeeping  is  done 
at  the  packing-shed.  The  order  sheet  is  kept  in  con- 
venient reach  at  the  packer's  right  and  as  the  orders  are 
filled  and  tags  attached  to  the  packages,  they  are  checked 
off  the  list.  The  work  thus  proceeds  systematically  and 
without  confusion  and  lost  motion. 

Office  methods. 

If  the  grower  is  sufficiently  well  known  throughout 
the  territory  which  he  supplies  or  desires  to  supply,  and 
his  stock  has  been  properly  advertised,  the  office  force 
will  be  well  occupied  from  the  middle  of  April  until 
July  1st.  Many  orders  will  be  booked  during  the  win- 
ter and  early  spring  months  and  these  will  be  tabulated 
for  immediate  attention  when  the  first  plants  are  ready 
to  be  drawn.  A  rush  of  orders  will,  however,  begin  to 
pile  in  with  the  beginning  of  early  planting  season  and 
at  this  time  the  grower  receives  the  best  prices  for  his 
plants.  These  orders  must  receive  prompt  attention. 
Nothing  is  so  valuable  to  a  commercial  grower  as  to  have 
the  reputation  of  giving  his  orders  prompt  and  faithful 
attention.  Many  telephone  and  telegraph  orders  will 
be  received  by  the  progressive  grower  and  these  must  be 
given  the  same  courteous  attention  as  the  mail  orders. 


88  The  Sweet  Potato 

The  business-like  plant-dealer  never  sends  a  customer 
one  variety  of  plant  when  another  has  been  ordered 
without  first  asking  whether  the  substitution  is  satisfac- 
tory. The  very  best  business  principles  must  be  used 
in  the  office  if  satisfied  customers  are  to  be  gained. 

The  office  force  tabulates  each  order  by  making  an 
order  sheet  in  duplicate.  One  copy  of  this  order-sheet 
is  sent  to  the  man  in  charge  of  the  packing-shed  together 
with  corresponding  shipping  tags.  One  system  of  hand- 
ling money  must  be  adopted  and  rigidly  adhered  to. 
It  is  best  that  all  orders  go  through  the  office  in  the  reg- 
ular prescribed  way,  and  no  plants  sold  directly  from 
the  beds  without  making  a  record  of  same.  Of  course 
the  particular  system  to  be  used  will  be  worked  out  in 
each  case  by  the  owner  in  such  a  manner  as  to  fit  his  spe- 
cific conditions.  As  with  any  other  business,  there  are 
many  possible  "  leaks  "  that  must  be  avoided  if  profit  is 
to  result. 

Advertising. 

Although  a  dealer  may  be  able  to  grow  the  most  per- 
fect plants  at  the  proper  time  and  season  and  with  a 
minimum  cost  for  production,  unless  he  can  dispose  of 
them  at  a  profitable  price,  his  enterprise  is  a  failure. 
It  should  not  be  concluded  that  advertising  in  its  proper 
sense  can  be  done  in  any  one  year  or  two  years  and 
through  newspapers  and  farm  journals  alone.  Any 
broadly  successful  business  is  gradually  built  up  through 
long  years  of  earnest  and  concerted  effort,  by  fair  deal- 
ing always  and  with  the  continued  aid  of  the  printed 
announcement.  A  satisfied  customer  is  the  best  ad- 
vertisement. The  classified  ad  columns  of  the  leading 
farm  weeklies  seem  to  be  one  of  the  most  popular  and 


Propagation  89 

efficient  advertising  mediums.  Some  growers  have 
fonnd  that  large  and  more  attractive  advertisements  in 
a  few  leading  daily  papers  having  a  wide  circulation 
are  highly  profitable.  Small  and  less  expensive  adver- 
tisements should  be  run  during  the  late  winter  and 
early  spring  months,  announcing  the  varieties  offered 
and  the  prices  booked  for  delivery  at  a  specified  time. 
For  a  few  weeks  before  the  rush  season  opens,  it  will 
be  profitable  to  run  a  good  advertisement  in  every  daily 
or  weekly  paper  published  in  the  immediate  vicinity. 
At  this  time  more  than  at  any  other,  the  advertising 
campaign  should  be  pushed. 


CHAPTER  V 
TILLAGE,  FERTILIZING  AND  ROTATION 

The  soil  adapted  to  sweet  potato  culture  is  usually 
easy  to  prepare,  in  about  the  same  way  as  for  corn  or 
cotton.  It  should  always  be  borne  in  mind  that  very 
thorough  preparation  is  repaid  in  the  ease  of  cultivation 
to  follow.  The  depth  of  cultivation  has  considerable  in- 
fluence on  the  character  of  the  product. 

If  the  soil  has  not  been  broken  deeply  before,  a  little 
more  should  be  plowed  each  succeeding  year  rather  than 
the  entire  depth  the  first  year.  The  land  may  first  be 
prepared  either  by  flat  breaking  or  by  ridges  thrown  up 
to  form  rows.  It  is  important  that  the  land  should  be 
harrowed  within  a  few  hours  after  plowing.  It  should 
be  thoroughly  pulverized,  and  this  may  be  done  shortly 
after  a  shower  while  the  lumps  and  clods  are  still  soft. 
After  this  work  has  been  completed,  the  soil  should  be 
mellow  to  a  depth  of  6  to  8  inches,  and  the  surface 
smooth  and  even. 

Preparation  for  planting. 

After  the  land  has  been  plowed  and  fitted  for  the 
sweet  potato  crop,  it  should  be  allowed  to  lie  idle  several 
days  before  planting.  If  potatoes  are  to  be  planted 
flat  for  level  culture,  only  a  harrow  and  a  marker  are 
necessary  for  planting.  The  harrow  should  be  run  both 
ways    and    the    surface    tlioroughly    pulverized.     The 

90 


Tillage,  Fertilizing  and  Rotation  91 

marking  may  be  done  either  with  a  one-horse  roller  rake- 
toothed  marker  or  a  disk-marker.  When  the  more  uni- 
versal ridge  method  is  used,  the  ridges  or  rows  are  made 
by  means  of  a  turning  plow  or  disk.  The  ridges  should 
be  turned  a  few  days  before  planting  in  order  that  the 
soil  may  have  time  to  settle.  Most  farmers  make  the 
ridges  whenever  the  land  is  in  working  condition,  and 
then  run  over  them  with  a  drag  or  roller  to  level  them, 
and  leave  a  suitable  place  to  set  out  the  plants.  By 
means  of  the  roller  or  drag,  from  four  to  eight  rows  can 
be  done  at  once,  according  to  the  nature  of  the  machine. 
A  drag  can  be  built  at  home  by  nailing  together  several 
pieces  of  2  X  4,  or  one  or  two  4X4  scantlings. 

In  small  patches  for  home  use,  ridges  are  often  leveled 
by  means  of  a  field  or  garden  hoe,  all  the  preparatory 
work  and  cultivation  being  done  by  a  one-horse  plow. 

Distance  and  method  of  planting.     (See  Plate  III.) 

When  level  culture  is  practiced,  plants  may  be  set  from 
24  to  30  inches  apart  in  each  direction.  On  the  eastern 
shore  of  Virginia,  Delaware  and  New  Jersey,  a  part  of 
the  crop  is  checked  24  inches  each  way,  therefore  re- 
quiring about  11,000  plants  to  the  acre.  When  the  crop 
is  grown  in  ridges,  it  is  customary  to  have  them  from 
30  to  40  inches  apart,  and  the  plants  from  12  to  18 
inches  in  the  row.  By  this  method  an  acre  will  require 
from  8000  to  12,500  plants,  the  average  acre  through- 
out the  Gulf  Coast  region  being  set  with  about  10,000 
plants. 

In  planting  for  level  cultivation,  the  location  for  the 
plants  is  indicated  by  cross  marks  made  by  running 
the  marker  in  two  directions  across  the  field,  the  marker 
being  at  right  angles.     When  planting  on  ridges,  the 


92  The  Sweet  Potato 

distance  of  the  plants  apart  may  he  found  by  running 
the  marker  across  the  rows. 

An  important  operation  to  be  watched  is  the  proper 
setting  out  of  the  plants  after  they  have  been  drawn 
from  the  seed-bed.  It  is  a  common  custom  throughout 
the  sweet  potato  region  to  set  just  before  a  rain  or  as 
soon  thereafter  as  the  land  will  permit.  It  is  essential 
to  have  the  roots  in  contact  with  moisture,  and  the  soil 
packed  firmly  around  the  plants.  If  the  ground  is  not 
wet,  it  may  be  necessary  to  haul  water  to  the  field  and 
pour  about  one-half  pint  around  each  plant. 

In  the  area  where  irrigation  is  practiced,  the  plants 
may  be  set  and  the  water  turned  on  which  will  insure 
the  growth  of  practically  all  the  plants. 

Setting  the  plants  in  the  field. 

When  only  an  acre  or  two  is  grown  for  home  use, 
hand-planting  will  answer  the  purpose  and  is  probably 
more  economical.  A  trowel  and  dibble  may  be  used  to 
open  and  pack  the  earth  around  the  roots ;  after  the  roots 
of  the  plants  are  thrust  into  the  hole  in  the  ridge,  the 
earth  should  be  pressed  firmly  around  them.  For 
hand-planting,  plants  are  dropped  ahead  of  the  setters, 
boys  and  girls  being  very  useful  for  this  work. 

Setting  out  one  acre  by  hand  is  considered  a  good 
day's  work  for  one  man.  A  part  of  the  undesirable 
work  by  hand  may  be  avoided  by  the  use  of  tongs. 
After  the  plants  have  been  dropped  on  the  rows,  the 
root  may  be  clamped  with  the  jaws  of  the  tongs  and 
thrust  into  the  ground.  This  saves  the  bending  of  the 
back  and  is  practically  as  fast  as  the  hand  work.  The 
tongs  should  be  of  wood  and  about  3  feet  in  length ;  the 
jaws  of  the  tongs  should  be  made  by  sawing  out  a  por- 


Tillage,  Fertilizing  and  Ixotaiion  93 

tioii  down  through  the  middle  of  the  stick.  This  will 
leave  jaws  on  either  side  that  stand  erect  but  are  readily 
clasped  together.  On  being  released  from  the  hand, 
thej  assume  their  natural  position.  An  instrument 
known  as  a  shovel  or  punch  may  sometimes  be  used. 
This  may  be  made  from  a  narrow  board  with  the  ends 
somewhat  sharpened,  with  which  a  hole  is  punched,  the 
root  inserted  in  the  hole  and  the  ground  packed  around 
it. 

When  a  large  acreage  is  planted,  hand-setting  is  too 
slow  and  expensive,  and  transplanting  machines  are 
used  which  are  capable  of  setting  several  acres  of  plants 
in  a  day.  With  these  machines  it  is  not  necessary  to 
wait  for  a  rain,  as  they  automatically  throw  a  small 
quantity  of  water  around  the  roots  of  each  plant  as  it 
is  being  set.  These  machines  will  set  from  three  to  five 
acres  a  day. 

Cultivation.     (Figs.  8-11.) 

After  the  potato  plants  are  set  in  the  field,  ordinary 


Figure  8. —  Five-tooth  cultivator. 


94 


The  Sweet  Potato 


methods  employed  for  other  crops  arc  all  that  are  neces- 
sary for  sweet  potato  cultivation.  In  the  South  it  is 
customary  to  keep  the  weeds  and  grass  from  the  row  by 


FiGUKE  9. —  Mulch  harrow. 

giving  at  least  one  hoeing.  The  potatoes  are  plowed 
two  or  three  times  or  until  the  ground  is  covered  by 
the  vines.  Cultivation  should  cease  when  the  vines  have 
thoroughly  covered  the  ground.  In  the  small  patches 
and  fields,  the  one-horse  plow  or  cultivator  is  ordinarily 
used,  or  sometimes  the  spring-toothed  harrow. 

In  flat  lands  on  the  coast  where  the  soil  is  wet,  farmers 
often  use  a  plow  to  throw  up  a  high  ridge.  While  this 
assists  in  drainage,  it  is  not  thought  to  be  of  much 
value  from  the  standpoint  of  cultivation. 

On  larger  farms  where  potatoes  are  grown  for  com- 
mercial purposes,  cultivation  is  done  by  one-  and  two- 
horse  cultivators.     In  this  way  a  row  is  completed  at 


Tillage,  Fertilizing  and  Rotation 


Figure  10. —  Diverse  spring-tooth  cultivator. 

one  passage  over  the  row,  practically  the  same  kind  of 
plows  being  used  as  on  the  single-stock  plow. 

It  is  customary  in  certain  localities  to  throw  two 
rows  of  vines  to  the  same  middle  and  cultivate  the  alter- 
nate middles  thus  left  free  or  clean.  In  some  sections 
the  vines  are  turned  from  one  side  of  the  row  to  the 


Figure   11. —  Five-tooth   cultivator   with   banker   attachment. 


96  The  Sweet  Potato 

other  while  plowing,  then  turned  back  after  the  plowing 
is  finished.  It  is  not  thought  advisable  to  turn  vines 
after  the  ground  is  thoroughly  covered.  After  the 
vines  have  become  large  enough  to  shade  the  ground, 
the  shade  will  kill  out  grass  and  weeds  and  keep  the 
surface  cool ;  it  is  not  necessary  to  cultivate  later  than 
this. 

Irrigation. 

In  some  arid  regions  where  sweet  potatoes  are  grown, 
it  is  necessary  to  supply  moisture  by  means  of  irri- 
gation. The  most  practictil  method  is  the  open  ditch, 
or  furrow  irrigation  with  water,  the  supply  coming 
from  some,  stream  or  lake.  The  greatest  quantity  of 
water  should  be  supplied  between  the  time  the  plants  are 
set  in  the  field  and  when  the  vines  thoroughly  cover  the 
ground.  Too  much  water  applied  during  the  latter 
part  of  the  summer  or  after  the  vines  have  covered  the 
ground  may  result  in  an  excessive  growth  and  a  small 
yield  of  stringy  potatoes.  It  is  preferable  that  the 
water  be  given  at  evening  or  on  cloudy  days.  For 
some  time  before  harvesting,  water  should  be  withheld 
altogether  in  order  that  the  roots  may  properly  ripen 
and  mature. 

FERTILIZERS 

Manure  is  the  foundation  of  successful  agriculture.^ 
Any  substance  added  to  the  soil  to  render  it  more 
fertile  may  properly  be  termed  a  fertilizer  or  a  manure. 
The  successful  producer  of  sweet  potatoes  or  of  any 
other  food  plant  secures  crops  that  command  a  selling 
price  in  advance  or  in  excess  of  their  production  cost 

1  Miller,  Farmers'  Bull.  999. 


Tillage,  Fertilizing  and  Rotation  97 

and  at  the  same  time  maintains  or  even  increases  the 
productivity  of  the  soil,  A  most  important  factor  in 
the  determination  of  profits  which  mnst  necessarily  be 
considered  by  the  business  farmer  of  to-day  is  the  rela- 
tion of  the  annual  outgoing  and  incoming  of  plant-food. 
Sound  business  principles  do  not  v^arrant  the  produc- 
tion of  increased  crops  unless  they  can  be  grown  at  a 
genuine  profit,  which  embodies  more  than  a  margin 
over  and  above  the  production  cost  in  the  way  of 
manures  and  labor  and  should  take  into  account  the  per- 
manent effect  on  the  productive  power  of  the  soil. 
These  facts  have  been  realized  in  a  practical  way,  per- 
haps without  any  special  understanding  of  the  scien- 
tific principles  involved,  by  many  of  the  sweet  potato 
growers  in  the  commercial  producton  centers.  This 
is  especially  true  of  the  New  Jersey,  Delaware  and  Vir- 
ginia growers  who  have  by  many  years  of  practical  pro- 
duction and  observation  learned  that  diligence  must  be 
exercised  in  the  rotation  of  crops  and  the  annual  appli- 
cation of  manures  if  the  quality  of  their  "  Nansemond 
sweets  "  is  to  meet  the  expectation  of  discriminating 
markets  and  the  productivity  of  their  land  is  to  be 
maintained.  In  areas  where  this  practical  observation 
has  not  been  facilitated  by  systematic  commercial  pro- 
duction, a  vast  improvement  in  the  proper  manuring 
of  the  sweet  potato  crop  must  be  effected  by  producers  if 
they  are  to  compete  successfully  with  their  more  ex- 
perienced neighbors.  This  phase  of  production  is  of 
especial  importance  to  the  naturally  favored  areas  of 
the  cut-over  pine-belt,  and  on  the  depleted  cotton  and 
tobacco  farms  of  the  South  where  the  prevailing 
climate  and  soil  conditions  aided  by  intelligent  and 
judicious    use    of    the    proper    manures    would    make 


98  The  Sweet  Potato 

possible  enormous  yields  of  a  high-class  quality  product. 

Although  fertilizers  have  become  a  necessity  in  the 
production  of  the  sweet  potato  when  maximum  profit  is 
derived,  certain  kinds  of  manures  may  result  in  actual 
injury  to  the  quality  and  so  reduce  the  selling  value  as 
to  make  the  crop  unprofitable.  Some  soils  may  yield 
profitably  to  the  application  of  one  food  element  while 
another  may  actually  retard  productive  growth.  For 
example,  it  has  been  found  that  liberal  application  of 
a  fertilizer  rich  in  potash  and  in  phosphorous  is  es- 
pecially profitable  on  a  soil  filled  with  undecayed  organic 
matter  such  as  one  that  has  had  a  green-manure  crop 
turned  under,  while  a  heavy  application  of  a  nitro- 
genous fertilizer  on  such  a  soil  might  result  in  the 
growth  of  very  luxuriant  vines  with  practically  no  pro- 
duction of  tubers.  It  is  now  believed  that  applications 
of  potash  on  certain  red  clay  soils  of  the  South,  although 
causing  increased  yield,  do  not  produce  an  increase  suf- 
ficient to  warrant  its  use,  notwithstanding  that  the 
sweet  potato  makes  heavy  demands  on  the  potash-con- 
tent of  the  soil.  Although  the  sweet  potato  responds 
readily  to  additions  of  organic  matter  to  the  soil,  such 
as  the  liberal  use  of  green-manures  and  barnyard  fer- 
tilizers, these  materials  cannot  be  applied  directly  to 
the  crop  without  reducing  the  quality  and  selling  value 
but  can  best  be  supplied  to  the  crop  immediately  pre- 
ceding the  potatoes.  It  is  now  concluded  that  nitrogen 
can,  other  things  being  equal,  be  supplied  most  econ- 
omically in  some  organic  form,  such  as  cotton-seed 
meal,  rather  than  nitrate  of  soda  or  sulfate  of  ammonia. 

To  understand  the  proper  manuring  of  a  crop  of 
sweet  potatoes  and  the  fertilizer  requirements  of  a  given 
rotation,    a    few   fundamental    principles    involved    in 


Tillage,  Fertilizing  and  Rotation  99 

fertilizer  standards  must  be  studied,  the  forms  of  plant- 
food  required,  the  sources  of  supply,  as  well  as  present 
day  methods  of  preparation,  commercial  sale  and  appli- 
cation. 

Kinds  of  fertilizers. 

Fertilizers  may  be  direct  or  indirect ;  complete  or  in- 
complete. A  fertilizer  that  supplies  available  plant- 
foods  directly  to  the  soil  is  known  as  direct.  Nitrate  of 
soda  is  a  good  example  of  this  type. 

A  fertilizer  that  benefits  growth  through  its  effects  on 
the  availability  of  the  plant-food  already  contained  in 
the  soil,  through  its  action  on  soil  acidity  or  by  im- 
proving the  mechanical  condition  of  the  soil,  is  known  as 
indirect.  Strictly  in  this  sense,  drainage,  proper  cul- 
ture or  humus  might  be  considered  fertilizers.  Lime  is 
the  most  commonly  used  commercial  fertilizer  of  the 
indirect  type. 

Although  plants  ordiuarily  require  about  fourteen 
different  food  elements  for  their  normal  growth,  only 
four  and  usually  only  three  ever  need  be  applied  arti- 
ficially. These  three  are  nitrogen,  phosphorus  and 
potassium;  the  fourth  is  calcium  in  the  form  of  lime. 
A  complete  fertilizer  is  one  containing  nitrogen,  phos- 
phorus and  potash  while  an  incomplete  one  supplies 
only  two  of  these  plant-foods. 

Function  and  form  of  plant-foods. 

Nitrogen,  phosphorus  and  potassium  are  known  as 
the  "  essential  "  fertilizing  constituents  since  they  are 
the  specific  plant-foods  most  likely  to  be  deficient  in 
soils  or  more  quickly  exhausted  by  the  production  and 
removal  of  crops.     Nitrogen  functions  most  largely  in 


100  The  Sweet  Potato 

the  production  of  vegetable  growth.  A  soil  overly  rich 
in  nitrogen  tends  to  produce  an  excess  growth  of  vines 
at  the  expense  of  the  roots.  Phosphorus  and  potash, 
while  present  in  the  vine  growth  and  more  or  less  es- 
sential to  it,  function  more  largely  in  the  make-up  of 
the  edible  roots,  and  in  the  case  of  other  crops  in  the 
formation  of  fruit  or  seed. 

Nitrogen,  which  in  commerce  is  the  most  expensive 
of  the  "  essential  "  elements,  exists  in  three  distinct 
forms ;  as  organic  matter,  as  ammonia  and  as  nitrate. 

Organic  nitrogen  occurs  in  all  plant  and  animal  forms 
and  its  availability  as  plant-food  depends  entirely  on 
the  rapidity  with  which  the  various  forms  decay.  In 
any  case,  its  availability  as  plant-food  comes  about 
more  slowly  than  the  two  other  forms  of  occurrence,  as 
nitrate  or  as  anomonia.  The  organic  forms  furnish 
some  of  the  more  valuable  sources  of  nitrogen  and  are 
of  value  where  the  more  quickly  available  forms  would 
be  of  relatively  little  importance.  Cotton-seed  meal, 
dried  blood,  fish  scrap  and  tankage  are  valuable  com- 
mercial sources  of  organic  nitrogen. 

Nitrogen  as  ammonia  is  more  readily  available  than 
the  organic  fonns.  In  fact,  organic  nitrogen  in  its  pro- 
cess of  decay  passes  through  the  ammonia  stage  in  be- 
coming available ;  it  is  one  of  the  first  products  that 
results  from  the  decay  of  organic  substances.  The 
commercial  nitrogen  in  this  form  is  obtain(>d  almost  en- 
tirely from  sulfate  of  ammonia.  It  is  readily  converted 
into  the  nitrate  form  and  quickly  becomes  available 
when  placed  in  the  soil.  This  form  of  nitrogen  is  es- 
pecially used  as  a  rainy-weather-available  fertilizer  for, 
until  it  changes  into  the  nitrate  form,  it  has  the  power  of 
combining  with  certain  minerals  and  organic  substances 


Tillage,  Fertilizing  and  Rotation  101 

in  the  soil  which  prevent  its  loss  bv  leaching-.  Commer- 
cial nitrate  of  ammonia  contains  about  20  per  cent  ni- 
trogen. 

In  the  form  of  nitrate,  nitrogen  is  directly  available 
to  the  plant  as  food.  It  is  the  most  soluble  form.  Ni- 
trate of  soda,  containing  an  average  of  about  15  per  ceot 
nitrogen,  is  the  most  common  commercially.  Neither 
nitrogen  as  ammonia  nor  as  nitrate  is  so  widely  used  for 
sweet  potatoes  as  are  the  organic  forms.  There  are  in- 
stances, however,  when  the  more  available  forms  are 
used,  either  because  of  their  cheaper  cost  or  because  of 
some  specific  purpose ;  as  giving  the  plant  a  rapid  start 
by  the  use  of  a  quickly  available  form  on  very  poor 
land.^  Cotton-seed  meal,  which  contains  on  an  average 
from  6  to  7  per  cent  nitrogen,  is  by  far  the  most  com- 
monly used  form  of  nitrogen  for  sweet  potatoes.  When 
the  cost  of  nitrogen  a  pound  in  this  form  is  not  greatly 
in  excess  of  the  cost  in  other  forms,  authorities  are  unan- 
imous in  recommending  it.  The  long  hot  season  during 
the  growing  period  furnish  conditions  best  suited  to  its 
rapid  decay. 

Phosphorus  exists  in  the  form  of  "  organic  "  phos- 
phates and  as  mineral  phosphates.  The  latter  are  so 
termed  in  contradistinction  to  the  organic  forms  be- 
cause of  their  lack  of  organic  or  animal  matter.  As  the 
organic  phosphates  are  seldom  used  in  sweet  potato  cul- 
ture, discussion  will  be  confined  to  the  mineral  forms. 

The  chief  sources  of  mineral  phosphates  in  this  coun- 
try are  the  raw  phosphate  rock  of  Florida  and  South 
Carolina,  phosphates  from  the  mines  of  Tennessee  and 
Thomas  slag  which  occurs  as  a  by-product  from  the 

1  For  more  exhaustive  study  of  forms  of  plant-food,  see  Farmers' 
Bull.  44. 


103  The  Sweet  Potato 

manufacture  of  steel  from  pliosphatic  iron  ores.  !N^one 
of  these  forms,  however,  is  used  in  the  raw  state  for 
sweet  potatoes. 

Superphosphates,  of  which  acid  phosphate  is  the  most 
common  commercial  form,  are  obtained  from  the  in- 
soluble or  very  slowly  soluble  raw  products  just  de- 
scribed. The  process  of  manufacture  consists  in  treat- 
ing the  finely  pulverized  raw  products  with  sulfuric  acid 
which  renders  soluble  the  phosphorus  which  they  con- 
tain. In  this  process  the  phosphoric  acid  obtained  is  a 
definite  chemical  compound  and  its  composition  is  the 
same  irrespective  of  its  raw  state.  Any  material  con- 
taining soluble  phosphoric  acid  as  its  chief  constituent 
may,  therefore,  be  termed  properly  a  superphosphate. 

Acid  phosphate,  containing  on  an  average  14  to  15 
per  cent  of  soluble  phosphoric  acid,  is  manufactured  by 
treating  1000  pounds  of  raw  phosphate  rock  with  1000 
pounds  of  a  dilute  solution  of  sulfuric  acid.  The  raw 
rock,  containing  about  30  per  cent  phosphorus  which  is 
very  slowly  soluble,  is  thereby  converted  into  a  com- 
pound having  about  one-half  as  much  total  phosphoras 
as  did  the  raw  rock  but  which  is  vastly  more  valuable 
as  a  fertilizer  for  ordinary  crops  because  of  the  availa- 
bility of  the  plant-food.  This  phosphate  is  the  form 
used  almost  exclusively  on  sweet  potatoes. 

Potash  exists  chiefly  in  two  forms,  as  chlorids  or 
muratcs  and  as  sulfates.  Though  the  availability  of 
the  potash  in  these  forms  is  about  equal,  the  respective 
elements  with  which  it  is  combined  in  the  two  forms 
exert  considerable  influence  on  its  use  for  particular 
crops. 

Tt  has  been  found  that  the  potash  combined  with 
chlorin  is  not  so  valuable  for  potatoes  as  the  sulfate 


Tillage,  Fertilizing  and  Rotation  103 

form.  It  seems  that  a  combination  of  chlorin  exerts 
an  undesirable  inflnonce  on  the  quality  of  the  crop. 
This  behavior  is  perhaps  more  noticeable  with  Irish 
potatoes  than  with  sweets.  The  supply  of  potash  is 
obtained  largely  from  the  potash  mines  of  northern 
Germany.  Sulfate  and  murate  of  potash,  kainit, 
sylvinit,  high-grade  sulfate  of  potash  and  double  sulfate 
of  potash  are  the  most  common  forms.  As  with  murate 
of  potash,  kainit  also  contains  large  amounts  of  chlorin, 
although  in  reality  the  potash  is  in  the  form  of  a 
sulfate. 

For  sweet  potatoes,  potash  is  best  applied  in  the  form 
of  sulfate.  It  gives  largest  returns  on  light  sandy 
soils  and  on  lands  with  a  high  humus-content.  Clay 
soils  are  usually  well  supplied  with  potash.  With  a 
good  clay  subsoil,  when  the  surface  is  sandy,  sweet 
potato  crops  do  not  respond  noticeably  to  applications 
of  potash,  especially  when  the  sand  is  not  deep  and 
plowing  has  brought  some  of  the  clay  to  the  surface. 

Potash  is  sometimes  applied  in  the  form  of  hard- 
wood ashes,  which  in  the  unleached  state  contains  about 
5  per  cent  potash.  This,  however,  is  usually  an  expen- 
sive medium  and  is  seldom  used  except  when  the  lime 
contained  is  decidedly  unleached,  when  it  contains  in 
addition  to  4  to  6  per  cent  potash,  about  30  per  cent 
lime  and  from  1  to  2  per  cent  phosphoric  acid. 

Commercial  fertilizers. 

Commercial  fertilizers  differ  from  farm  and  green- 
manures  in  that  they  exist  in  a  form  readily  exchanged 
and  handled  in  commerce.     The  following  table  ^  gives 
1  Farmers'  Bull.  44. 


104 


27ie  Sweet  Potato 


the  most  common  commercial  fertilizers  and  their  re- 
spective contents  of  manurial  constituents : 

Table    XII. —  Composition   of   the   Principal    Commercial 
Fertilizing  Materials. 


Nitro- 
gen 

Phosphoric  acid. 

Potash. 

Fertilizing  material. 

Avail- 
able. 

Insol- 
uble. 

Total. 

Chlorin. 

Supplying  nitrogen : 

Per 

cent. 
15..5-1G.0 

Prr 
cent. 

Per 
cent. 

Per 
cent. 

Per 
cent. 

Per 
cent. 

Dried  blood   (high  grade). 

12.0-14.0 

10. 0-11. n 

3.0-  5.0 
l.C-  2.0 
11.0-14.0 
6.0-  S.O 
1.5-  2.0 
1.0-  1.5 

26.0-28.0 

13.0-16.0 
33  0-35  0 

Concentrated    tankage 

5.0-  6.0 
7  0-90 
6.5-  7.5 

5.0-  e.o 

2-  3.0 
1-  1.5 

Supplying    phosphoric    acid: 
South   Carolina  rock   phos- 

26-2S 

1-  3 

33   3."i 

South     Carolina    rock     su 
perphosphate      (dissolved 
South       Carolina       rock 

12-15 

Florida    land     rock    phos- 

2i;-32 

1-  4 
32-36 

1-  2 

1.5-17 
16-20 

2-  3 

26.0-32.0 

16.0-20.0 
32.0-36.0 

17.0-18.0 
20.0-25.0 
22.0-29.0 
15.0-17.0 
11.4-23.0 

Florida          superphosphate 
(dissolved    Florida    phos 

14-16 

Boneblack    superphosphate 
(dissolved    boneblack)... 

■2.5-4.5 
1.5-  2.5 
2.0-  3.0 

15-17 

5-  S 

6-  9 
13-15 

Supplying  potash: 

4S-52.0 

48-52.0 

26-30.0 
12-12.5 
16-20.0 
20-30.0 
2-  8.0 
1-  2  0 
5-  8.0 

45  0-48.0 

Sulfate     of    potash     (high 

.5-  1.5 

Sulfate      of      potash      and 

1.5-  2.5 

Kainit 

30.0-32.0 

42.0-46  0 

7.0-  9.0 
1.0-  2.0 
1.0-  1.5 
3.0-  5.0 

Wood-ashes     (unleached)2 

■VVnnfl-nsViun      (\e"\rhpi\'\2 

2.0-  3.0 

1  In  Kood  Tliomas  slag  at  least  80  per  cent  of  the  phosphoric  acid  should 
be  soluble  in  ammonium   citrate,   i.  e.,   available. 

2  Cotton-hull    ashes    contain    about   10    per    cent   of   lime ;    unleached    wood 
ashes,  30  to  35  per  cent;  and  leached  wood  ashes,  35  to  40  per  cent. 


Tillage,  Fertilizing  and  Eolation  105 

The  percentage  of  available  plant-food  elements  in  a 
complete  fertilizer  is  usually  marked  on  the  container. 
State  laws  require  this  of  manufacturers  and  state  in- 
spection is  usually  very  rigid.  A  2-8-10  formula  means 
2  per  cent  nitrogen,  8  per  cent  phosphorus  and  10  per 
cent  potash.  The  nitrogen  is  often  listed  as  ammonia, 
which  in  interpreting  formulas  is  considered  to  be  about 
^/47  as  valuable  as  nitrogen.  Fertilizers  should  always 
be  purchased  on  the  basis  of  the  available  plant-food 
which  they  contain  and  not  according  to  the  price  or 
brand  of  the  fertilizer.  The  fertilizer  lowest  in  price 
is  often  the  most  expensive  medium  through  which  plant- 
food  may  be  purchased.  In  general,  the  actual  plant- 
food  contained  in  higher-grade  fertilizers  is  least  ex- 


Home-mixtng  of  fertilizers. 

Thorough  familiarity  with  fertilizing  constituents, 
better  facilities  for  handling  and  the  ability  to  pur- 
chase in  large  quantities,  makes  legitimate  the  commer- 
cial manufacture  of  complete  ready-mixed  fertilizers. 
In  spite  of  this,  many  sweet  potato  growers  can  save 
money  by  mixing  their  manures  at  home  and  if  intelli- 
gent care  is  exercised  as  good  results  can  be  secured  with 
the  home-mixed  goods  as  with  that  purchased  ready- 
mixed.  In  many  cases  there  may  be  an  actual  improve- 
ment in  results  as  well  as  saving  in  cost,  since  the 
"  carriers  "  are  known  and  mixing  can  be  done  to  suit 
specific  conditions. 

The  approximate  composition  of  the  fertilizers  de- 
sired must  first  be  decided  on  and  the  form  in  which 
each  constituent  is  to  be  applied  must  be  determined 
1  Bull.  392,  N.  Y.  Exp.  Sta.,  1914. 


106  The  Sweet  Potato 

by   the   convenience    and   availability   of   the   possible 
materials  which  will  supply  the  desired  plant-food. 

For  the  northern  commercial  sections,  Miller^  rec- 
ommends "  a  fertilizer  analyzing  2  to  4  per  cent  of 
nitrogen,  8  per  cent  phosphoric  acid  and,  when  avail- 
able, 8  to  10  per  cent  of  potash."  Assuming  that  cot- 
ton-seed meal  is  the  most  convenient  source  of  organic 
nitrogen  (which  is  preferred  to  inorganic  forms  for 
sweets),  and  acid  phosphate  and  sulfate  of  potash  the 
best  carriers  of  phosphoric  acid  and  potash  respectively, 
the  following  fertilizer  may  be  mixed : 

Composition  of  fertilizers,  4  per  cent  nitrogen,  8  per  cent 
phosphoric  acid  and  10  per  cent  potash: 

(1)  Use  cotton-seed  meal  containing  6.5  per 
cent  of  nitrogen. 

(2)  Use  acid  phosphate  containing  16  per  cent 
phosphoric  acid. 

(3)  Use  sulfate  of  potash  containing  46  per  cent 
potash. 

(4)  20  Cwt.  (in  one  ton)  X  2  per  cent  N  = 
40  lb.  nitrogen  -^  6.5  (nitrogen)  in  c.  s.  meal 

=  615  lbs.  c.  s.  meal 615  lbs. 

(5)  20  Cwt.  (in  one  ton)  X  8  per  cent  phos- 
phoric =  160  lbs.  phosphorous  -=-  16  (phos- 
phoric   in    acid    phosphate)    =    1000    lbs. 

acid  phosphate   1000  lbs. 

(6)  20  Cwt.  (in  one  ton)  X  10  per  cent  K.  20 
=  200  lbs.  potash  -f-  50  (potash  in  sulfate 

of  potash)  =  400  lbs.  sulfate  potash 400  lbs. 

2015  lbs. 

By  calculating  the  cost  of  such  a  fertilizer  with  local 
1  Farmers'  Bull.  999. 


Tillage,  Fertilizing  and  Rotation  107 

prevailing  prices  of  the  ingredients  and  comparing  this 
cost  plus  labor  of  mixing  with  the  manufacturers'  price 
for  a  ready-mixed  product  of  the  same  analysis,  the 
economy  of  home-mixing  could  be  determined.  Some 
soils  would,  perhaps,  require  no  nitrogen  at  all,  in  which 
case  the  calculation  for  the  other  two  elements  would 
be  made  exactly  as  before  and  the  deficiency  in  making 
a  ton  would  be  made  up  by  the  use  of  a  filler.  Often 
in  buying  ready-mixed  fertilizers,  the  producer  has  to 
pay  freight  on  a  "  filler  "  which  is  of  comparatively  no 
value  as  a  fertilizer. 

Mixtures  adapted  to  the  growing  of  sweet  potatoes  on 
most  soils  may  be  mixed  in  the  following  proportions: 

1000  pounds  of  16  per  cent  acid  phosphate 
600  pounds  of  cotton-seed  meal 
400  pounds  of  sulfate  of  potash. 

Total,  2000  pounds. 
200  pounds  of  sulfate  of  ammonia  about  25  per 

cent  pure 
200  pounds  of  dried  blood 
1200  pounds  of  acid  phosphate  about  10  or  12  per 
cent  pure 
400  pounds  of  muriate  or  sulfate  of  potash  about 
50  per  cent  pure 

Total,  2000  pounds. 

This  last  mixture  should  analyze  about  4  per  cent 
nitrogen,  6  per  cent  phosphoric  acid  and  10  per  cent 
potash.     The  nitrogen  may  be  left  out  or  reduced. 

What  fertilizer  to  apply. 

It  is  impossible  to  give  any  specific  fertilizer  ration 
best  to  use  on  a  crop  of  sweet  potatoes.     Even  a  chera- 


108  The  Sweet  Potato 

ical  analysis  of  a  specific  soil  would  be  of  little  practical 
value  in  determining-  the  "  best  "  fertilizer.  Every 
grower  must  make  a  study  of  his  individual  soil  re- 
quirements by  noting  "  results  "  rather  than  by  theoret- 
ical calculations.  For  this  reason  it  has  been  thought 
best  to  give  as  briefly  as  possible  the  fundamentals  un- 
derlying fertilization  and  with  this  knowledge  each 
grower  can  be  guided  in  the  intelligent  manuring  of 
specific  fields.  ' 

In  the  commercial  sections  of  northern  production 
areas  where  the  growing  season  is  comparatively  short, 
more  liberal  application  of  manures  will  be  profitable 
than  in  the  South.  When  rapidity  of  growth,  earliness 
and  high  quality  are  important  factors,  even  the  most 
fertile  soils  contain  too  little  quickly  available  plant- 
food  for  maximum  yields.  In  such  cases,  more  liberal 
and  careful  application  of  commercial  manures  must 
be  resorted  to. 

Humus. 

It  has  been  said  that  "  humus  is  just  as  necessary  to 
make  soil  fertility  as  water  is  to  make  lime  and  sand 
into  plaster."  This  is  especially  true  of  land  on  which 
the  best  yields  of  sweet  potatoes  are  to  be  secured.  Al- 
though the  chemistry  of  humus  is  not  thoroughly  under- 
stood, it  is  known  to  be  a  very  powerful  factor  in  ren- 
dering soil  loose  and  friable  (when  well-drained)  ;  it 
supplies  plant-food  in  the  form  of  nitrogen ;  it  combines 
with  many  of  the  other  fertilizing  elements,  making 
them  available  and  effective;  it  is  very  important  in  con- 
trolling the  moisture-content  of  the  soil,  in  furnishing 
food  for  friendly  bacteria^  in  enhancing  the  physical 


Tillage,  Fertilizing  and  Rotation  109 

Condition  generally  and  it  has  an  important  influence  on 
soil  temperatures. 

Although  a  liberal  supply  of  humus  is  very  desirable 
on  sweet  potato  land,  it  should  be  well  decayed,  the  soil 
well-drained,  and  it  should  not  be  acid  or  sour.  Humus 
becomes  worthless  with  many  croppings  and  its  supply 
in  the  soil  must  be  renewed  from  time  to  time.  This 
is  best  done  by  the  application  of  barnyard  manure  and 
the  use  of  green  cover-crops  turned  under.  However, 
such  applications  of  humus  should  be  made  to  crops  pre- 
ceding the  sweet  potatoes  in  the  rotation  if  it  is  to  decay 
properly  and  be  of  most  value. 

Green-manures. 

The  question  of  providing  in  the  rotation  a  legu- 
minous crop  to  supply  needed  nitrogen  and  humus  has 
been  briefly  discussed  under  rotation.  Even  when  these 
crops  are  removed  from  the  land,  an  actual  gain  in 
nitrogenous  fertility  results.  The  Ehode  Island  Ex- 
periment Station,  in  a  five-year  pot  experiment,  found 
that  cowpeas  and  soybeans  grown  on  land  resulted  in 
a  gain  in  nitrogen.  "  The  approximate  five-year  net 
gain  of  nitrogen  in  the  presence  of  these  two  crops 
and  the  vetch  which  was  grown  alternately  with  each, 
was  a  ton  of  nitrogen  per  acre,  about  seven-tenths  of 
which  was  contained  in  the  twenty-five  tons  of  moisture- 
free  summer  crops  removed,  and  the  remainder  in  the 
soil  itself.  These  quantities  should  be  considered  with 
reference  to  the  following  facts,  namely :  the  soil  in  the 
pots  Avas  10  inches  deep,  somewhat  deeper  than  the 
surface  soil  in  many  localities;  the  winter  vetch  was 
grown  in  a  heated  greenhouse;  and  furthermore,  suf- 


110  The  Sweet  Potato 

ficient  water  was  given  to  supply  all  needs  of  the 
plants,"  ^  In  many  sections  of  the  South,  the  growth 
of  leguminous  crops  in  the  sweet  potato  rotation  would 
be  a  most  desirable  means  of  supplying  both  nitrogen 
and  humus,  which  are  much  needed  on  many  of  these 
soils.  If  the  crops  in  rotation  are  corn,  cotton,  oats  or 
wheat,  leguminous  crops  should  be  sown  with  these,  or 
after  they  are  harvested,  in  which  case  they  might  also 
be  used  as  a  winter  cover-crop.  Velvet  beans,  peas  or 
clover  may  be  planted  with  the  corn,  or  clover  may  fol- 
low oats  or  wheat.  Very  good  results  are  secured  by 
turning  under  a  heavy  crop  of  crimson  clover  early  in 
the  spring.  Green-manuring,  however,  consists  of  more 
than  growing  a  leguminous  crop  which  is  removed  from 
the  soil.  It  means  the  growing  of  a  crop  on  the  land 
which  is  plowed  under.  Many  fields  of  so  called  "  worn- 
out  "  land  could  be  made  to  produce  bountiful  yields  of 
high  quality  sweets  by  the  use  of  one  or  two  crops  of 
legume  turned  under  as  manures. 

Other  materials  as  fertilizers. 

Stable-manure  J  though  supplying  organic  matter  in 
its  most  desirable  form  and  also  adding  nitrogen  and 
smaller  quantities  of  other  food  elements  to  the  soil, 
should  never  be  applied  directly  to  a  crop  of  sweet 
potatoes.  When  so  applied  it  has  a  tendency  to  cause 
too  rapid  growth,  resulting  in  large  rough  tubers  of 
poor  quality.  When  applied  excessively,  vine  growth  is 
over-stimulated  at  the  expense  of  the  tubers.  Stable- 
manure  is  best  applied  to  the  crop  immediately  preced- 
ing the  sweets  and  even  then  it  should  be  well  rotted. 
Well-rotted  stable  manure  may  be  used  at  the  rate  of 

1  Bull.  147,  Pv.  T.  Exp.  Sta. 


Tillage,  Fertilizing  and  Rotation  111 

10  to  15  wagon-loads  to  the  acre.  It  may  be  applied 
broadcast,  and  harrowed  into  the  soil,  or  drilled  into  the 
rows  before  bedding. 

Peat,  muck  and  leaf-mold. —  Clay  soils  and  others 
having  a  tendency  to  compactness  and  those  deficient  in 
organic  matter  can  often  be  improved  for  the  growth  of 
sweet  potatoes  by  an  application  of  peat,  muck,  or  leaf- 
mold.  Sometimes  these  substitutes  contain  as  high  as 
4  per  cent  nitrogen.  Their  chief  value,  however,  is  in 
the  humus  which  they  contain.  The  distance  which 
such  substitutes  have  to  be  hauled  will  determine  the 
advisability  of  use. 

Poultry  manure. — The  value  of  poultry  manure  is 
too  often  unappreciated  by  farmers.  This  substance  is 
rich  in  nitrogen  and  phosphoric  acid.  It  is  valuable  as 
a  fertilizer  for  sweets  in  the  ISTorth  where  they  are 
grown  as  a  garden  vegetable.  If  the  full  utility  of  this 
fertilizer  is  received,  care  must  be  taken  of  it,  as  a 
large  part  of  the  nitrogen  may  be  lost  by  evaporation. 
Poultry  manure,  or  any  other  barnyard  manures  should 
never  be  mixed  with  ashes  since  they  contain  alkalies 
which  increase  fermentation,  causing  a  loss  of  nitrogen. 

Hardwood  ashes  may  be  applied  to  sweet  potato  land 
at  the  rate  of  1200  to  2000  pounds  to  the  acre.  A 
good  grade  of  wood-ashes  should  analyze  from  6  per  cent 
to  8  per  cent  of  available  potash.  They  also  contain 
considerable  lime.  The  food  value  may  be  reduced  by 
excessive  leaching. 

Lime  is  also  applied  to  sweet  potato  land  when  a  large 
amount  of  green  material  has  been  turned  under  for 
organic  matter.  This  neutralizes  the  sourness  that 
often  is  caused  by  the  gi'een  crop.  From  one  to  two 
tons  may  be  applied  to  the  acre.     Lime  present  in  the 


112  The  Sweet  Potato 

soil  hastens  the  maturity  of  the  crop  and  increases  the 
yield.  On  poor  soil,  lime  and  potash  work  together  to 
produce  uniform  sizes  and  shape.  Lime,  for  the  best 
results,  should  be  applied  the  year  previous  to  planting- 
sweet  potatoes. 

Application  of  fertilizers.      (Plate  III.) 

Since  the  sweet  potato  plant  when  transplanted  in  the 
field  is  ready  to  begin  growth,  all  fertilizers  are  best 
applied  sometime  before  the  plants  are  set.  The  com- 
mon practice*  is  to  apply  commercial  fertilizers  in  the 
drill  at  the  time  of  making  the  rows.  This  is  ordinarily 
done  by  distributing  the  fertilizer  in  the  middles  be- 
tween rows,  mixing  it  with  the  soil  by  stirring  with  a 
scooter  or  bull-tong-ue,  and  then  bedding  on  top  of  it  by 
throwing  two  furrows  together  with  a  turn  plow.  It 
is  very  important  that  kainit  (when  used  as  source  of 
potash)  be  thoroughly  mixed  with  the  soil  before  plant- 
ing, as  cases  have  been  reported  in  which  this  fertilizer 
injured  the  crop. 

ROTATION 

The  growing  of  a  series  of  crops  on  the  same  land  in 
definite  order  throughout  a  period  of  years  constitutes 
what  is  termed  crop  rotation. 

Proper  rotation  is  now  recognized  to-  be  a  necessity  to 
maximum  production  and  efficiency  witli  all  crops.  In 
fact,  it  is  quite  as  important  to  the  permanent  welfare 
of  the  soil  as  to  the  yield  and  quality  of  the  plants 
grown,  and  the  kind  of  rotation  practiced  will  have 
fully  as  much  influence  on  both  as  docs  cultivation  or 
fertilization. 

A  seed-bed  may  be   perfectly  prepared;   plant-food 


Tillage,  Fertilizing  and  Rotation  113 

may  be  present  in  abundance ;  the  seasons  may  be  ideal ; 
and  still  a  complete  failure  or  a  greatly  reduced  yield 
may  be  the  reward  because  each  year  the  field  has  had 
to  nourish  the  same  kind  of  crop,  supplying  it  with  the 
same  amount  of  the  same  food  elements  and  receiving 
in  return  the  particular  toxin  or  poison  which  is  given 
off  by  the  plant  in  question.  Each  plant  takes  from 
the  soil  its  special  kind  of  food  and  throws  off  certain 
root  excretions,  corresponding  to  perspiration  in  ani- 
mals, which  are  poisonous  to  that  particular  plant  but 
which  perhaps  would  be  unharmful  to  any  other  species. 
Each  plant  exerts  a  certain  influence  on  the  mechanical 
condition  of  the  soil  caused  by  the  development  of  its 
peculiar  root  system  which  varies  with  different  crops. 
Alternation  of  deep  and  shallow-rooted  crops  in  the 
rotation  require  the  use  of  other  layers  of  soil.  Each 
plant  has  certain  insect  enemies  and  is  subject  to  certain 
fungous  diseases  which  naturally  become  worse  if  the 
plant  crop  is  grown  in  the  same  place  year  after  year. 
Some  crops  are  more  exhaustive  on  the  humus  supply 
of  soils  than  others,  and  rotation  enables  the  main- 
tenance of  this  humus. 

Proper  rotation  facilitates  diversification  of  crops 
which  is  essential  to  the  proper  distribution  of  farm 
labor. 

Plant-food. 

The  demand  on  soil  for  plant-foods  from  year  to 
year  is  varied  by  rotation.  An  "  exhausted  "  soil  is 
frequently  depleted  in  some  one  food  element  due  to 
growing  continually  some  crop  that  uses  more  of  that 
element  than  it  does  of  other  plant-foods.  Such  a  soil 
is  often  exhausted  only  for  the  particular  crop  which 


114  The  Sweet  Potato 

has  been  grown  without  alternation.  A  thousand 
pounds  of  sweet  potatoes  contain  2.9  pounds  of  nitrogen, 
.9  pounds  of  phosphoric  acid  and  5.1  pounds  of  potash, 
while  a  similar  amount  of  Dent  corn  contains  16.2 
pounds  of  nitrogen,  6.9  pounds  of  phosphoric  acid  and  4 
pounds  of  potash.^  Thus  it  is  seen  that  sweet  potatoes 
remove  from  the  soil  about  two-thirds  more  potash  than 
nitrogen,  while  corn  removes  more  than  four  times  as 
much  nitrogen  as  potash.  It  would  appear  that  a  con- 
tinuous cropping  of  corn  would  quickly  exhaust  the 
nitrogen  supply,  while  successive  crops  year  after  year 
of  sweet  potatoes  would  tend  to  deplete  the  supply  of 
potash  more  quickly  than  the  other  food  elements. 
However,  this  consideration  in  favor  of  crop  rotation 
is  not  considered  of  as  much  importance  as  formerly  for 
the  increased  yields  resulting  will  ordinarily  take  from 
the  soil  inore  actual  plant-food  than  would  be  used  by 
the  smaller  crops  were  rotation  not  practiced.  The  fact, 
however,  that  plant-food  in  the  soil  is  continually  being 
made  available  and  that  deficient  crops  use  the  elements 
in  varying  proportions  may  be  of  importance. 

Root  excretions. 

The  accumulation  in  the  soil  of  certain  root  poisons 
or  toxins  may  be  avoided  by  rotation.  Frequently  when 
the  soil  has  been  well  fertilized  and  diseases  kept  out, 
small  yields  of  sweet  potatoes  are  secured  on  a  piece  of 
ground  after  several  years  continuous  cropping. 
Although  little  definite  information  is  available  on  the 
subject,  it  is  known  that  the  roots  of  a  plant  throw  off 
waste  matters  and  that  these  excretions  seem  to  be  self- 
poisoning  to  the  plant.     Other  plants,  however,  are  not 

1  "  Feeds  and  Feeding,"  Henry  and  Morrison. 


Tillage,  Fertilizing  and  Rotation  115 

noticeably  injured  by  this  poison  and  after  a  few  years 
cropping  in  other  varieties  the  toxid  effect  is  destroyed 
by  natural  soil  forces. 

Mechanical  effect  on  soil. 

The  prevailing  opinion  that  "  sweets  "  are  hard  on 
land  is  not  without  foundation.  Not  only  are  large 
amounts  of  nitrogen  and  potash  removed  but  frequently 
the  crop  is  not  dug  until  late  and  the  ground  is  often 
left  bare  all  winter  when  the  leaching  rains  rob  the  soil 
of  its  available  plant-food. 

Hogs  are  often  left  in  the  potato  fields  in  wet  weather 
when  their  rooting  causes  the  soil  to  become  hard  and 
baked  when  it  is  dried  out.  The  soil  should  never  be 
molested  when  muddy  either  by  animals  or  otherwise. 

On  heavy  soils,  the  vines,  especially  when  heavily 
manured,  become  very  rank  and  when  turned  under 
cause  too  much  acid  in  the  soil.  Under  such  conditions, 
an  application  of  raw  phosphate  rock  would  be  advis- 
able. Sweet  potato  land  should  be  amply  supplied  with 
organic  matter  but  it  should  be  well  decayed  and  the 
soil  should  be  loose  and  mellow. 

Proper  rotation  of  crops  provides  for  sowing  a  winter 
cover-crop  to  prevent  leaching;  for  the  growth  of 
legumes  to  be  turned  under  and  allowed  to  decay 
thoroughly ;  and  for  the  alternation  of  deep  and  shallow- 
rooted  crops  which  will  preserve  and  improve,  the 
mechanical  condition  of  the  soil,  making  it  easier  and 
more  economical  to  cultivate  and  allowing  the  produc- 
tion of  a  crop  of  the  best  quality. 

Insect,  fungous  and  weed  enemies. 

One  of  the  most  important  advantages  of  crop  rota- 


116  The  Sweet  Potato 

tion  with  the  sweet  potato  is  the  controlling  of  insect 
pests  and  fungous  diseases  which  in  sections  seriously 
hamper  the  development  of  the  industry.  In  speaking 
of  control  measures  for  the  sweet  potato  weevil,  which 
in  Texas  alone  is  exacting  an  annual  toll  of  nearly  20 
per  cent  of  the  crop,  Chittenden  ^  writes  "  Rotation  of 
crops  is  a  necessary  measure  in  the  eradication  of  this 
pest;  indeed,  injury  may  be  prevented  to  a  large  ex- 
tent by  the  selection  of  the  field  for  planting."  (See 
Chapter  VII.)  Miller  ^  says,  "A  rotation  in  which 
sweet  potatoes  are  gro\vn  on  the  land  once  in  three  or 
four  years  combined  with  seed  selection  and  hot-bed 
sanitation,  is  effective  in  preventing  loss  from  stem-rot, 
black-rot  and  other  injurious  diseases."  The  New  Jer- 
sey Station  recommends  a  rotation  calling  for  sweet 
potatoes  not  oftener  than  once  in  four  or  five  years  for 
old  sections  and  every  three  years  for  new  ground  if 
disease  is  to  be  controlled. 

Some  crops  are  favorable  to  the  growth  of  accom- 
panying weeds  which  are  likely  to  become  firmly  estab- 
lished if  the  crop  is  continually  grown  on  this  same  land. 
In  the  South,  crops  of  the  short-vined  varieties  of  sweet 
potatoes  may  be  almost  completely  choked  out  by  Ber- 
muda-grass which  can  easily  be  held  in  check  by  the 
use  of  a  heavy  cover-crop  such  as  cowpeas.  Johnson- 
grass,  "  nut-grass  "  and  "  Kerless  "  weeds  are  obnoxious 
enemies  of  the  sweet  potato.  All  can  be  controlled  and 
sometimes  completely  eradicated  by  proper  rotation. 

Rotation  to  he  used. 

The  crop  rotation  with  sweet  potatoes  will  necessarily 
have  to  be  determined  by  the  individual  grower.     It  will 

1  F.  H.  Chittenden,  Farmers'  Bull.  1020,  p.  18. 

2  Fred  E.  Miller,  Farmers'  Bull.  999,  p.  5. 


Tillage,  Fertilizing  and  Rotation  117' 

be  governed  by  the  prevailing  soil  and  climatic  condi- 
tions ;  by  the  kind  of  farming  practiced ;  by  the  demand 
and  market  for  particular  crops  that  might  be  grown; 
by  the  inclination,  taste  or  preference  of  the  individual ; 
by  the  land  and  equipment  available ;  by  the  condition  of 
his  land  and  other  circumstances  which  can  only  be  de- 
cided by  the  individual. 

The  cut-over  pine  lands  of  the  South  are  preeminently 
suited  to  the  production  of  "  sweets "  and  even  the 
"  worn-out  "  cotton  and  tobacco  farms  make  good  yields, 
when  rotation  includes  leguminous  crops  for  increasing 
the  humus-content  of  the  soil.  Newly  cleared  land  in 
this  region  produces  heavy  crops.  As  the  clovers  do 
not  thrive  on  a  large  part  of  this  la:nd  when  planted  so 
late  (sweet  potatoes  in  this  section  are  harvested  in 
jSTovember),  such  crops  as  oats  and  rye  have  to  be  de- 
pended on  for  winter  cover.  In  Virginia  and  regions 
farther  north,  when  potatoes  are  dug  for  the  early 
markets,  crimson  clover  may  be  sown  for  a  cover-crop 
provided  the  potatoes  are  off  by  September  1  to  15  in 
JSTew  Jersey,  Delaware  and  Maryland,  and  by  Septem- 
ber 30  in  southern  Virginia.  Where  the  potatoes  oc- 
cupy the  land  too  late  for  planting  crimson  clover,  a 
cover-crop  of  rye  or  of  oats  and  vetch  should  be  used. 

The  following  suggested  three-  and  four-year  rota- 
tions are  taken  from  Farmers  Bulletin  999  of  the 
United  States  Department  of  Agriculture : 

A.  For  the  cotton-belt,  where  sweet  potatoes  are  grown  as 
a  farm  crop : 

1.  First  Year,     (a)   Cotton,  followed  by  rye  for  winter  pas- 
ture or  as  a  crop  to  turn  under;  or 
(b)   Corn,    with    cowpeas   or   velvet   beans 
planted  as  a  soil-improving  crops. 


118  The  Sweet  Potato 

Second    Year.     Sweet   potatoes    followed   by    a   winter 

cover-crop  of  rye  or  oats  and  vetch. 
Third  Year.     Oats,  followed  by  peanuts  or  cowpeas. 
2,  First  Year.     Sweet  potatoes  followed  by  a  winter  crop 
of  rye  or  oats  and  vetch. 

Second  Year.     Cotton,  with  rye  sown  between  the  rows 

for  winter  pasture  or  to  turn  under. 
Third  Year.     Corn  with  cowpeas  or  velvet  beans  planted 
as  a  soil-improving  crop. 
AA.     Four-year    rotation    for    the    southern    sweet-potato 
section : 

First  Year.     Sweet  potatoes. 

Second    Year.     Winter    oats,    followed   by    peanuts    or 

cowpeas. 
Third  Year.     Cotton,  with  bur  clover  between  the  rows. 
Fourth  Year.     Corn,  with  cowpeas  or  velvet  beans  be- 
tween the  rows. 
AAA.     Three-year  rotation  for  the  eastern  shore  of  Vir- 
ginia and  Maryland: 

First  Year.     Sweet  potatoes,  followed  by  crimson  clover 

or  rye  as  a  winter  cover-crop. 
Second   Year.     Early    Irish   potatoes.     In    many   farms 
corn  is  planted  between  the  rows  of  potatoes  at  the 
last  cultivation ;  on  other  farms  the  potatoes  are  fol- 
lowed by  fall  vegetables. 
Third  Year.     Winter  oats,  followed  by  cowpeas  for  hay. 

These  rotations  are  merely  suggestive  and  will  neces- 
sarily be  changed  according  to  the  existing  influences 
governing  any  case.  Miller  conchides,  "  In  planning  a 
sweet  potato  rotation,  the  importance  of  plowing  under  a 
soil-improving  crop  once  every  two  or  three  years  should 
be  borne  in  mind.  The  crops  to  include  in  this  rotation 
will  vary  according  to  local  conditions.  Wherever 
practicable  a  leguminous  crop,  such  as  cowpeas,  soy- 
beans, velvet  beans,  or  crimson  clover  should  be  used  in 
order  to  supply  nitrogen  as  well  as  humus." 


Tillage,  Fertilizing  and  Rotation  119 

CONCLUSION 

In  growing  sweet  potatoes,  quality,  which  is  measured 
by  size,  shape  and  cooking,  is  a  very  important  consid- 
eration. These  characteristics  are  largely  influenced 
by  the  soil,  the  rotation  followed,  and  the  fertilizer 
applied.  An  abundance  of  phosphoric  acid  and  potash 
with  smaller  amounts  of  not  too  quickly  available  nitro- 
gen are  essential.  A  yield  of  200  bushels  of  sweet  po- 
tatoes, not  including  vines,  removes  from  the  soil  approx- 
imately 30  pounds  of  nitrogen,  10  pounds  of  phosphoric 
acid  and  30  pounds  of  potash.  Fertilizers  containing 
a  liberal  supply  of  potash  in  comparison  to  the  other 
elements  seem  to  give  best  returns  under  average  con- 
ditions, though  clay  soils  do  not  respond  so  readily  to 
this  element.  In  general,  the  best  growers  have  found 
a  small  amount  of  nitrogen  and  a  larger  percentage  of 
phosphorus  and  potash  to  give  most  profitable  returns. 
A  quantity  of  each  element  somewhat  in  excess  of  the 
actual  amount  removed  from  the  soil  by  the  plant  should 
be  applied,  as  some  will  be  lost  by  leaching.  Twenty 
pounds  of  pure  nitrogen  to  the  acre  is  the  maximum  that 
should  be  used  if  high  quality  is  not  to  be  sacrificed  to  ex- 
cessive yields.  The  New  Jersey  Station  has  found  that 
commercial  fertilizers  alone  can  be  depended  on  to  fur- 
nish plant-food,  but  barnyard  and  green-manures  are 
valuable  for  supplying  organic  matter  or  humus.  Or- 
ganic nitrogen  is  preferred  to  the  more  soluble  forms. 
Commercial  fertilizer  is  best  applied  in  the  drill  before 
putting  out  the  plants,  while  stable  and  green-manures 
should  be  applied  to  crops  preceding  the  sweet  potatoes 
in  the  rotation.  Organic  matter  in  the  soil  should  be 
well  decayed. 


CHAPTEK  VI 
VARIETIES 

The  question  of  varieties  is  largely  a  local  problem 
depending  on  special  conditions  and  on  the  require- 
ments of  the  market  served.  Considerable  confusion 
exists  both  in  this  country  and  in  the  insular  possessions 
with  reference  to  varietal  characteristics.  This'  is  due 
in  a  large  part  to  the  fact  that  the  sweet  potato  is  sub- 
ject to  sudden  mutation  or  the  appearance  of  sports 
giving  rise  to  many  new  varieties,  which  may  or  may 
not  continue  in  existence.  Often  even  the  name  for 
well-known  varieties  is  extremely  local,  varying  for  the 
same  variety  in  different  sections.  Many  growers  have 
undertaken  the  improvement  of  some  standard  variety 
and  after  a  few  years'  selection  have  given  it  an  entirely 
new  name.  These  influences  combined  have  given  rise 
to  a  vast  number  of  varieties,  many  times  differing 
from  some  other  only  in  the  local  adoption  of  a  par- 
ticular name.  Eor  instance,  the  Pumpkin  yam,  the 
Georgia  Split-Leaf  and  the  East  Texas  yam  are  identical 
but  are  sold  from  the  different  sections  under  the  various 
names.  In  Porto  Rico  a  great  many  varieties  are  found 
but  only  the  Mamey  varieties,  namely  the-  Mameyona 
or  large  Mamey  and  the  Mameyita  or  small  Mamey, 
and  also  the  Blanca  or  white,  are  known  by  the  same 
name  all  over  the  island. 

Several  tentative  classifications  for  varieties  have 
120 


Varieties  121 

been  suggested  by  various  writers  but  no  key  has  yet 
been  made  sufficiently  complete  to  rely  on  in  accurate 
classification.^  Roughly  speaking,  the  distinguishing 
characterization  of  various  varieties  are  included  in: 
(1)  the  length  of  vine,  which  may  be  either  long  or 
bunch;  (2)  the  shape  of  leaves,  which  are  either  deep 
cut,  shouldered  or  entire;  (3)  the  texture  of  the  meat, 
which  is  either  sirupy,  mealy  or  intermediate;  (4)  the 
color  of  the  flesh,  which  may  be  yellow,  white  or  mottled 
white  and  yellow;  and  (5)  the  color  of  the  skin,  which  is 
white,  yellowish,  light  red  or  purple.  Many  minor 
characters  may  be  noted,  such  as  prominence  of  leaf- 
veins,  color  of  leaf-veins,  and  tint  of  leaves.  In  order 
to  make  a  treatise  on  varieties  as  practical  as  possible, 
it  has  been  thought  best  to  give  all  of  the  available  in- 
formation on  the  better  known  kinds,  even  though  some 
of  these  varieties  are  only  known  locally  by  the  name 
given. 

The  descriptions  given  below  are  in  somewhat  the 
form  of  notes  as  made  by  the  authors  from  observation, 
elaborated  in  cases  by  descriptions  from  other  authori- 
ties. All  available  descriptions  of  varieties  except  a 
very  few  well  known  ones  are  admittedly  incomplete  and 
the  notes  on  characteristics  and  importance  constitute 
only  such  information  as  is  known  to  be  reliable  and  ac- 
curate. A  longer  study  and  more  systematic  effort  on 
the  part  of  investigators  is  sure  to  give  some  very  valu- 
able data  on  varietal  characteristics  in  the  future,  and 
if  the  descriptions  given   here  seem  incomplete  it  is 

1  A  letter  from  Jno.  H.  Beattie  of  the  Bureau  of  Plant  Industry, 
Washington,  D.  C,  to  the  author,  dated  July  30,  1919,  says,  "  Dur- 
ing the  present  season  we  are  planning  to  test  our  variety  key  out, 
and  if  it  shows  the  same  results  as  it  did  last  year,  we  will  publish 
the  material." 


122  The  Sweet  Potato 

hoped  the  reader  will  remember  that  only  time  and 
study  can  bring  about  a  standardized  varietal  character- 
ization with  any  plant  so  subject  to  change  by  climate, 
mutation  and  selection  as  is  the  sweet  potato. 

Anguilla. —  This  variety  seems  to  have  almost  dis- 
appeared from  the  market.  It  was  formerly  well 
known  on  the  eastern  coast  where  it  grew  to  great  size. 
In  this  respect  it  was  similar  to  the  Peabody,  but  dif- 
fered in  its  white  skin  and  white  flesh.  This  variety  is 
characterized  by  the  immense  size  the  potatoes  attain, 
the  heavy  crop  and  the  poor  quality  as  judged  by  the 
general  southern  taste.  It  is  rapidly  going  out  of  culti- 
vation except  as  hog-feed. 

Aekansas  Beauty. —  This  is  a  long  tapering  potato, 
very  smooth  and  yellowish  in  color.  The  roots,  which 
are  very  uniform  in  size,  are  borne  in  clusters.  The 
skin  is  pronounced  yellow,  while  the  flesh  is  light  yel- 
low and  very  delicate  looking.  The  vine  growth  is  good 
but  it  is  a  poor  yielder. 

Big  Stem  Jersey. —  This  potato  is  distinguished  by 
being  the  most  widely  cultivated  of  all  varieties  for  the 
northern  markets.  Growers  on  the  eastern  shore  have 
long  grown  this  and  its  near  relative,  the  Little  Stem 
Jersey.  The  Virginia  Truck  Experiment  Station  at 
Norfolk  has  given  the  following  ofiicial  description  of 
the  variety :  ''  Vines  long,  heavy,  leaves  large ; 
potatoes  long,  spindle  shaped,  irregular,  often  veiny, 
many  very  large.  Skin  bright  yellow,  flesh  creamy  to 
pinkish.  Table  quality  fair,  dry.  A  fairly  heavy 
yielder,  especially  for  early  crop.  Not  adapted  to  ham- 
per pack.  There  are  pink-flcshed  strains  especially 
good  for  canning,  since  the  flesh  of  the  potato  is  of  a 
very  attractive  color  for  this  purpose.     The  table  qual- 


Varieties  123 

ity  of  these  strains  is  also  superior."  ^  In  addition  to 
the  above  description,  it  might  be  added  that  the  vines 
are  long,  slender  and  creeping.  The  leaves  are  small, 
green  on  both  sides  and  entire.  The  potatoes  are  late 
in  season  to  mature.  This  variety  is  a  heavy  yielder 
and  can  be  grown  farther  North  with  better  success  than 
the  moist-fleshed  varieties.     (See  Plate  IV.) 

Black  Spanish. —  This  variety  is  identical  with  the 
Nigger  Killer,  or  Negro  Choker,  described  below. 

Braziliaist. —  The  roots  of  the  Brazilian  are  large, 
smooth,  roundish  and  uniform  in  shape.  The  skin  is 
light  yellow;  the  flesh  white.  It  is  a  hardy  variety 
and  very  prolific,  with  a  luxriant  vine  growth. 

Ceeola. —  This  is  a  heavy  yielding  variety,  very 
valuable  for  stock-food.  The  foliage  is  characterized  as 
follows:  "  Stem  single,  rather  thin,  white  below  sur- 
face, deep  ruby  red  above  surface  of  ground.  Leaf 
somewhat  inclined  to  be  triangular.  Margins  entire. 
Medium  green  above  and  grayish  green  underneath. 
Vines  light  green,  rather  large.  Petioles  medium  thick, 
very  long,  light  green  color."  ^ 

DooLEY  Yam. —  One  of  the  best  yielders  and  keepers 
among  the  long  list  of  strictly  southern  grown  sweets  is 
the  Dooley.  This  is  an  old  variety  and  is  well  known 
and  extensively  produced  in  all  of  the  southern  states. 
The  vines  are  slender  but  very  long,  often  attaining  a 
length  of  15  feet  or  more.  They  are  dark  green  and 
the  leaves  are  entire  with  three  to  five  tiny  marginal 
points  according  to  the  age  of  the  leaf.  The  dark 
green  vines  blend  into  a  greenish-purple  color  as  the 

i.T.  C.  Johnson  and  J.  T.  Rosa,  Jr.,  Bull.  19,  p.  414,  Va.  Truck 
Exp.  Sta. 

2  T.  C.  Johnson,  Va,  Truck  Exp.  Sta.,  information  to  author. 


124  The  Sweet  Potato 

roots  come  to  maturity.  The  potatoes  are  fair  in  size, 
being  short,  smooth  and  spindle-shaped.  The  flesh  is 
dark  yellow  to  salmon  in  color,  very  soft,  sweet  and 
juicy  when  baked.  The  Dooley  is  not  an  early  maturer. 
(See  Plate  IV.) 

Delaware. — ■  This  is  one  of  the  dry  mealy  types  or- 
iginating from  the  original  Nansemond,  or  Jersey 
Sweet,  of  Maryland  and  Virginia. 

ruLLEKTo«sr  Yellow  Yam. —  The  potatoes  are  very 
long  in  proportion  to  their  diameter.  They  are  borne 
in  clusters  and  are  very  prolific.  The  skin  is  light 
yellow;  the  flesh  white  spotted  with  yellow,  and  sweet 
and  sugary  in  nature. 

Florida  Yam. —  In  a  series  of  variety  tests  conducted 
by  C.  E.  Brehm,  of  the  Tennessee  Station,  the  Florida 
yam  gro\\Ti  under  identical  conditions  with  a  number  of 
other  kinds,  was  only  equalled  in  yield  by  the  Nancy 
Hall.  Brehm  says :  "  Although  seedmen  differentiate 
between  the  varieties  Florida  yam  and  Nancy  Hall,  I 
am  confident  that  there  is  no  difference.  The  only 
difference  that  I  can  see  is  that  when  shipments  are 
made  North  they  call  sweet  potatoes  of  this  variety 
Nancy  Hall  and  when  shipped  South  they  call  them 
Florida  yams.  From  the  standpoint  of  appearance 
and  yield  they  are  identical." 

General  Grant. —  This  variety  has  been  noticed  to 
produce  very  few  small  potatoes.  The  roots  are  either 
of  good  size  or  they  are  strings.  The  large  potatoes  are 
smooth  and  well-shaped.  The  strings  are  worthless. 
The  skin  is  very  light  yellow  and  the  flesh  pure  white. 
The  vine  growth  is  prolific  but  the  yield  of  potatoes  is 
small. 

Gold  Skin. —  This  variety  belongs  to  the  Nansemond 


Varieties  125 

class  together  with  the  Yellow  and  Tied  jSTanscmond,  the 
Delaware,  Big  and  Small  Stem  Jersey  and  the  Red 
Nose.  The  name  "  Gold  Skin  "  seems  to  be  more  of  a 
trade  name  for  "  Jersey  Sweets  "  rather  than  a  term 
designating  a  distinct  variety  with  outstanding  varietal 
characteristics.  Gold  Skins  are  sold  extensively  on 
the  northern  markets.  They  have  the  mealy  flesh  char- 
acteristic of  the  Nansemond  potatoes. 

Geokgia  ok  Split-Leaf  Yam. —  This  variety  is  ex- 
tensively grown  for  home  use  throughout  the  South 
Atlantic  and  Gulf  states  and  is  known  under  several 
local  names,  such  as  the  Georgia  Buck,  Split-Leaf  and 
East  Texas  Yam.  The  vines  grow  long  and  slender; 
the  stems  are  light  green  in  color;  the  leaves  are  the 
same  color  and  seven-parted,  being  very  deeply  cut. 
Johnson  ^  describes  the  vine  growth  as  follows :  "  Stem 
branching,  bushy,  rather  slender,  portion  below  surface 
of  ground  is  white  to  pinkish,  and  that  above  surface  is 
pinkish  to  green.  Leaf  is  deeply  divided,  prominent 
shoulders;  margin  entire;  color  medium  green  up- 
per surface,  grayish  green  lower  surface;  veins  heavy, 
light  green;  petioles  thick,  moderate  length,  light 
brownish  color."  This  variety  is  a  good  yielder  and  is 
adapted  to  gr'owing  for  home  use  and  for  markets  de- 
manding a  sweet,  very  moist  potato. 

Hayman  oe  Southern  Queen. —  The  Hayman  and 
Southern  Queen  are  identical,  having  whitish  skin  and 
creamy  flesh.  This  variety  and  the  Nancy  Hall  are  the 
only  "  yam  "  kinds  grown  in  the  eastern  shore  produc- 
tion section.  The  Hayman  has  long  been  well  known  in 
that  section  but  years  ago  it  was  taken  up  by  B.  K. 
Bliss,  then  a  leading  seedman  in  New  York  City,  and 
1  T,  C.  Johnson,  Va.  Truck  Exp.  Sta.,  information  to  author. 


126  The  Sweet  Potato 

sent  out  as  a  new  potato  under  the  name  of  Southern 
Queen.  It  is  now  known  in  manj  sections  by  the  latter 
name.  It  is  very  earlj,  unusually  productive  and  is 
considered  one  of  the  earliest  varieties  to  keep  in  storage. 
It  is  much  improved  in  eating  quality  by  storage  and 
though  not  a  very  choice  eating  potato  in  fall  and  early 
winter,  it  becomes  very  good  indeed  in  late  winter  and 
spring.  It  is  of  a  very  light  color  outside,  presenting  a 
grayish-white  rather  than  yellow  appearance.  The  flesh 
is  pale  yellow.  The  vine  growth  is  heavy.  The  tubers 
are  inclined  to  become  over-large  in  rich  soil,  unless 
early  digging  is  practiced.      (Plate  IV.) 

Jewel  Yam. —  This  is  a  yellow  potato  very  like  the 
dry  Nansemond  but  with  the  sweet  soft  flesh  of  the 
yams.  It  was  formerly  grown  to  a  limited  extent 
through  the  Carolinas.  It  is  a  heavy  yielder  with  prom- 
inent veins  and  is  almost  identical  in  appearance  and 
quality  with  the  Yellow  Barbadoes. 

Key  West  Yam. —  This  is  one  of  the  sweet  juicy 
potatoes  similar  to  the  Porto  Rico.  It  is  a  good  yielder 
and  sells  well  on  the  southwestern  markets.  It  is  largely 
grown  in  the  Manhattan  sweet  potato  section  of  Kansas 
and  perhaps  equally  extensively  in  other  parts  of  the 
Southwest.  It  is  also  well  known  on  the  eastern  coast. 
Because  of  the  heavy  yield,  it  is  largely  used  as  stock 
food.  ''  Stems  branching  and  bushy,  quite  thick ;  color 
below  ground  pink,  above  ground  deep  ruby  red ;  leaf 
auriculate,  sharply  pointed,  mostly  shouldered ;  mar- 
gins very  finely  serrated ;  dark  green  upper  surface, 
light  green  under  surface;  veins  prominent,  purplish 
color;  petioles  long,  thick,  with  green  purplish  tinge."  ^ 

1  T.  C.  Johnson,  Va.  Truck  Exp.  Sta.,  information  to  author. 


Plate  V. —  Diseases  of  sweet  potatoes,  a,  A  section  through  a 
sweet  potato  showing  the  blackened  ring  just  below  the  surface 
caused  by  the  stem-rot  fungus,  h,  A  sweet  potato  plant  showing 
the  characteristic  symptoms  of  stem-rot.  c.  Sweet  potato  black-rot. 
Small  sweet  potato  plant  showing  the  characteristic  blackening  of 
the  underground  part  of  the  stem.  d.  Soft-rot.  A  sweet  potato 
showing  the  moldy  growth  of  the  fungus  causing  soft-rot.  e. 
Soil-splotch. 


Varieties 


127 


LiTTXE  Stem  Jersey. —  The  Little  and  Big  Stem 
Jerseys  are  extensively  grown  for  the  northern  markets 
by  all  farmers  in  the 
eastern  shore  sweet  po- 
tato district,  where  the 
Eastern  Shore  of  Vir- 
ginia ProduceExehange 
has  done  much  to  stand- 
ardize the  production. 
Bulletin  19  of  the  Vir- 
ginia Truck  Experi- 
ment Station  gives  the 
following'  description  of 
the  variety :  "  Vines 
long,  slender,  leaves 
small ;  potatoes  uni- 
formly medium  sized, 
regular,  rounded  to  spindle  shaped;  bright  yellow  skin, 

creamy    flesh,     a    moderate 

yielder;  table  quality  good, 
dry.  This  variety  is  espe- 
cially adapted  for  shipping 
in  the  hamper  pack  to  north- 
ern markets."  The"  vine 
growth  is  similar  to  that  of 
the  Big  Stem  Jersey  except 
that  it  is  more  slender.  The 
potatoes  are  smaller,  more 
uniform,  smoother  and  less 
veiny  than  the  Big  Stem  Jer- 
sey,    according    to    Miller.^ 

1  Fred  E.  Miller,  Farmers'  Bull.  999,  p.  28. 


Figure  12. —  A  hill  of  healthy- 
Little  Stem  Jerseys  having  more 
than  five  potatoes  of  marketable 
size.  Fifty  hills  of  such  po- 
tatoes will  give  a  barrel  of  mar- 
ketable potatoes  and  some  culls. 
Such  healthy  high-yielding  hills 
of  uniform  potatoes  are  especi- 
ally good  for  seed. 


Figure  13.— A  hill  of 
healthy  Little  Stem  Jerseys 
with  potatoes  of  good  shape, 
but  not  lai'ge  enough  to  mar- 
ket as  primes.  This  photo- 
graph is  the  same  magnifi- 
cation as  Fig.   12. 


1S8  The  Sweet  Potato 

Plate  IV  shows  two  types  of  Little  Stem  Jerseys  (listed 
Yellow  Jerseys)  generally  grown.  One  represents  the 
long  spindle  type,  and  the  other  a  short  chunky  strain. 
(See  Figs.  12  and  13.) 

Meyebs  Early. —  This  is  a  sweet,  rich,  yellow- 
fleshed  sort  resembling  in  character  and  quality  the 
Nancy  Hall.  It  is  a  selected  strain  of  the  Nancy  Hall 
and  is  almost  identical  with  it.  It  is  known  throughout 
Georgia,  but  is  not  widely  distributed  in  other  states. 
The  vine's  have  short  nodes  rather  close  together,  and 
with  medium  to  small  "  entire  "  leaves.  The  Meyers 
Early  is  said  to  grow  a  little  longer  than  the  Nancy  Hall 
and  the  veins  on  the  roots  are  more  pronounced.  In 
fact,  the  description  of  a  well-grown  Nancy  Hall  potato 
will  fit  the  Meyers  Early  very  well. 

Nancy  Haljl. —  This  is  the  most  popular  of  all  the 
yellow  "  yam  "  varieties.  When  cooked,  the  flesh  re- 
sembles closely  that  of  the  Pumpkin  yam  of  Georgia 
and  the  Norton  yam  of  Norfh  Carolina.  It  does  not 
resemble  these  before  cooking,  however.  This  variety 
naturally  grows  short  and  chunky  and  the  skin  is  pale 
yellow  with  stray  streaks  of  pale  pink.  The  flesh  is 
deep  pumpkin  yellow  when  cooked.  The  Nancy  Hall, 
under  field  conditions,  is  outstanding  in  producing  a 
greater  amount  of  No.  1  bakers  with  fewer  jumbos  and 
culls.  The  potatoes  are  of  good  shape,  rather  prolific 
and  are  very  early  maturers.  The  vine  growth  is  luxu- 
riant. The  vines  are  medium  long  (3  to  5  feet)  and 
green  except  for  a  purple  stain  at  the  junction  of  the 
blade  and  petioles.     The  leaves  are  entire.     (See  Plate 

Nansemond  or  Jers.ey  Sweet. —  The  original  Nan- 


Varieties  139 

semond,  or  the  old  yellow  sweet  potato  of  Maryland  and 
Virginia,  is  a  dry  yellow  potato  popular  in  the  northern 
markets.  This  potato,  renamed  in  New  Jersey,  has 
given  rise  to  the  Delaware  and  the  Ked  Nose  varieties 
and  to  the  various  other  strains  of  the  Jersey  potatoes. 

NiGGEK  Killer. —  The  Nigger  Killer,  or  Nigger 
Choker,  has  a  purplish  red  skin  and  the  whitest  flesh  of 
any  potato.  It  is  very  dry  but  really  sweeter  than  the 
dry  yellow  varieties.  The  vines  are  very  long,  vigorous 
and  dark  purple  in  color.  The  potatoes  are  long,  cylin- 
drical and  crooked.  The  quality  is  poor,  the  variety 
being  grown  mostly  for  stock-food. 

Norton  Yam. —  This  variety  belongs  to  the  pumpkin 
colored  yams,  and  is  largely  grown  and  sold  through- 
out North  Carolina.  It  has  a  yellow  skin  and  the  flesh 
is  dark  pumpkin  colored  when  cooked. 

Old  Fashioned  Yellow  Yam. —  "  Stem  is  medium 
thick,  white  below  soil  surface  and  purplish  above. 
Leaf  is  very  deeply  divided,  with  three  lobes  and  two 
shoulders;  margin  entire,  light  green  above  and  gray 
green  under  surface;  veins  moderately  heavy,  light 
green  in  color;  petioles  are  thin,  rather  short,  light 
purplish  in  color."  ^ 

Peabody. —  This  potato  grows  to  an  immense  size, 
has  yellow  flesh,  red  skin,  and  is  very  dry  and  tasteless. 
It  is  often  sold  on  the  Raleigh,  North  Carolina,  market, 
when  about  one-fourth  gi*own,  as  there  are  usually  no 
good  potatoes  on  the  market  at  that  time.  When  fully 
grown,  it  will  not  sell  for  table  use  in  the  South  but  is 
frequently  used  as  food  for  hogs,  the  animals  being 
turned  on  the  fields  to  gather  the  roots  as  desired. 

1  T.  C.  Johnson,  Va.  Truck  Exp.  Sta. 


130  The  Sweet  Potato 

PiEESON. —  This  kind  resembles  quite  closely  the  Red 
Bermuda  described  below.  The  roots  are  light  yellow, 
well  shaped,  but  often  very  much  crooked  and  rough, 
with  light  yellow  flesh.  The  Pierson  comes  early  and 
finds  some  sale  on  the  extra  early  markets.  It  is  not  a 
heavy  yielder.  Johnson  describes  the  vine  growth  as 
follows :  "  Stem  single,  long,  branching  rather  thick, 
white  below  surface,  bright  reddish  to  purplish  above 
surface  of  ground.  Leaf  auriculate,  very  sharply 
pointed;  margins  entire;  upper  surface  of  leaf  is  dull 
green  with  purplish  pink  near  edge ;  lower  surface  gTay 
green;  veins  prominent,  medium  size;  petioles  slender, 
rather  long,  light  green,  with  purplish  tints." 

PoLO'. —  This  is  medium  to  large  in  size,  very  smooth, 
the  roots  rather  round  and  the  skin  and  flesh  white. 
The  vine  growth  is  luxuriant. 

Porto  Rico. —  Growers  throughout  southern 
Georgia,  Alabama  and  Mississippi  and  in  northeast 
Texas  have  in  recent  years  become  enthusiastic  over  the 
possibilities  of  the  Porto  Rico  potato.  It  is  said  al- 
ways to  give  a  good  yield  on  almost  any  soil,  although 
some  growers  claim  it  does  not  thrive  on  new  ground. 
It  not  only  yields  well  but  is  a  fair  keeper,  ships  well 
and  is  good  as  soon  as  dug.  This  variety,  though  not 
as  widely  known  as  the  Nancy  Hall  and  the  Nanse- 
mond,  is  very  rapidly  becoming  popular  on  the  big 
markets.  The  Porto  Rico,  however,  seems  to  be  very 
susceptible  to  attacks  from  the  sweet  potato  root-borer 
or  sweet  potato  weevil.  The  potatoes  are  medium  large, 
rounded,  regular,  deep  salmon  skin,  very  rich  salmon 
flesh,  sweet  and  juicy  and  in  the  South  are  considered 
very  choice  for  baking.     ( See  Plate  IV. ) 


Varieties  131 

Pride  op  Kansas. —  This  variety  is  ^rown  to  a 
limited  extent  in  certain  parts  of  Kansas  where  it 
originated.  It  is  not  a  standard  variety  and  is  not 
known  and  demanded  on  the  markets  outside  of  the 
purely  local  trade  in  the  sections  where  it  is  grown. 

Pumpkin  Yam. —  This  is  a  yellow  or  pumpkin- 
colored  sort  similar  in  color  of  roots  to  the  N'ancy  Hall. 
The  vines  are  long  and  the  leaves  entire.  The  stems 
are  green  and  hairy  and  the  leaves  are  green  on  both 
sides.  The  roots  are  medium  sized,  -smooth  and  well 
formed  with  prominent  bright-yellow  veins.  The  flesh 
is  mottled  yellow  and  white  with  yellow  predominating. 
The  potatoes  are  formed  unusually  deep  in  the  ground 
and  for  this  reason  are  not  so  readily  attacked  by  the 
sweet  potato  weevil,  though  the  roots  seem  quite  sus- 
ceptible to  fungous  diseases.  This  variety  is  very 
sweet,  very  moist  and  soft  in  texture.      (See  Plate  IV.) 

PuKPLE  Yam. —  This  potato  grows  very  long  in  pro- 
portion to  its  diameter.  The  skin  is  purple;  the  flesh 
white.  It  is  a  very  poor  yielder.  The  roots  are  borne 
near  the  surface  of  the  ground,  making  the  soil  crack 
open  more  than  is  customary  with  heavier  yielding 
varieties.  The  vines  are  large  in  size  but  the  stems 
are  spaced  far  apart  with  few  leaves. 

Eed  Bermuda. —  This  is  especially  adapted  for  use 
as  stock-food.  It  is  a  very  heavy  yielder,  the  vine 
growth  is  vigorous  and  the  potatoes  seem  unusually 
hardy  and  free  from  disease.  This  variety  belongs  to 
the  "  yam "  group  but  it  not  so  sweet  and  juicy  as 
the  Porto  Kico.  The  roots  are  rose  red  and  the  flesh 
light  yellow.  This  potato  will  thrive  farther  north 
than  most  of  the  so-called  yams. 


133  The  Sweet  Potato 

Red  Brazil. —  "  Stems  single,  thin,  light  pink  below 
surface  of  ground,  deep  ruby  red  above  surface. 
Leaves  long  and  sharply  pointed;  margins  finely  ser- 
rated; leaves  are  light  green  to  purplish  above  and 
grayish  green  on  under  surface;  veins  are  prominent, 
purplish  in  color;  petioles  thin,  medium  length,  with 
purplish  color."  ^ 

Eed  Caeolina. —  The  variety  is  nothing  more  than 
the  Red  Jersey  sold  under  a  name  indicating  its  place 
of  production. 

Red  Jersey  or  Red  E'ansemond. —  This  variety 
was  a  bud  sport  from  the  Yellow  I^ansemond.  The 
vines  are  identical  in  appearance  and  the  taste  of  the 
flesh  is  quite  similar.  This  variety  is  popular  on 
markets  which  show  preference  for  a  red-skinned 
potato.  It  is  a  heavy  yielder  and  finds  more  sales 
on  home  markets  than  in  shipping.     (See  Plate  IV.) 

Red  Nose. —  Among  the  offsprings  of  the  old 
original  jSTansemond,  or  Jersey  Sweet,  is  the  Red  Xose. 
This  is  a  yellow-fleshed  yellow-skinned  sort  with  brown- 
ish-red blotches  around  the  neck. 

Shanghai. —  The  vine  growth  is  very  luxuriant, 
the  stems  growing  large  and  vigorously.  The  roots 
resemble  those  of  the  I^igger  Killer  in  shape,  grow- 
ing very  long  and  cylindrical,  but  in  color  they  are 
almost  white.  The  meat  is  yellowish-white  but  turns 
a  rich  creamy  yellow  on  cooking.  It  looks  better  than 
it  tastes,  as  the  flavor  is  rather  poor  and  it  is  somewhat 
dry  and  mealy.  It  is  a  good  yielder  and  is  used  to 
a  limited  extent  in  the  Gulf  coastal  regions  of  Alabama, 
Mississippi,     Georgia     and     Florida     for     stock-food. 

iT.  C.  Johnson,  Va.  Truck  Exp.  Sta. 


Varieties  133 

Shanghor  Yam. —  Keitt  describes  this  potato  as  be- 
ing "  A  somewhat  irregularly  shaped,  white  fleshed 
variety,  skin  slightly  yellow.  Much  larger  percentage 
of  large  to  small  tubers  than  that  of  White  Spanish. 
Seems  entirely  free  from  disease.  The  potato  is  not 
what  is  usually  called  a  yam,  for  it  analyzed  high  in 
starch  and  low  in  sugar.     It  is  not  prolific."  ^ 

Tennessee  I^otciileaf. —  This  potato  is  described 
by  Keitt  as :  "  Eather  small,  somewhat  stringy  pota- 
toes, which  are  borne  in  large  clusters.  It  is  a  yellow 
fleshed  variety.  Was  attacked  by  a  white  rot  before 
gathering.  Very  prolific,  but  makes  very  little  growth 
of  vines." 

ToLMAN  Variety  of  Old  Spanish. —  The  Spanish 
potatoes  constitute  a  distinct  class  characterized  by  the 
slim  narrow  crooked  potatoes  with  white  skin  inclined 
to  pinkish  shades  and  with  grayish- white  flesh.  The 
Tolman  strain  is  very  similar  to  its  close  relative,  the 
White  Barbadoes. 

Triumph. —  The  Triumph  is  the  earliest  potato  on 
the  market  and  being  white  and  mealy  sells  well  in 
the  North.  It  is  not  so  good  for  the  southern  trade 
and  does  not  sell  so  well  after  the  early  season  demand  is 
over.  The  Triumph  is  not  a  good  keeper.  It  is  a 
heavy  yielder  and  is  noted  for  the  prominence  of  the 
veins  and  the  large  size  of  the  roots  when  left  in  the 
ground  until  mature.  The  vines  are  bushy  in  nature 
and  the  leaves  deeply  cut.  Because  of  the  bushy 
nature  of  the  vines,  they  are  very  easy  to  cultivate. 
The  vine  growth  has  been  described  as  follows :  "  Leaf 
auriculate,  pointed,  double  shoulders;  margin  irregular 
1  T.  E.  Keitt,  S.  C.  Exp.  Sta.,  Bull.  146,  1908. 


134  The  Sweet  Potato 

and  serrated ;  color,  upper  surface  deep  green ;  lower 
surface,  light  green ;  veins,  heavy,  deep  red ;  size, 
medium  to  rather  small;  petioles,  thick,  long,  green 
and  purplish."  '     (See  Plate  IV.) 

ViNELEss  Bunch  Yams. —  The  Vineless  seems  to  be 
a  sport  from  the  ]S[orton  Yam,  as  bunch  sorts  frequently 
appear  among  the  ISTortons.  The  roots  in  appearance 
and  quality  are  identical  with  the  Nortons.  This 
variety  is  described  as  follows :  ^  —  "  Long,  tapering, 
uniform ;  but  rather  small  tubers ;  having  a  yellow  skin, 
and  white  and  light  yellow  mottled  with  white  flesh,  with 
some  deeper  yellow  spots.  Not  much  vine  growth  and  a 
shy  bearer."     (See  Plate  IV.) 

White  Bakbadoes. —  This  is  another  of  the  Spanish 
potatoes  and  is  almost  identical,  if  not  quite  so,  with 
the  Tolman  variety  of  Old  Spanish.  Both  the  white 
and  yellow  Barbadoes  are  thicker  in  shape  than  the 
Old  Spanish.  The  White  Barbadoes  is  pale  whitish  in 
flesh,  and  yellow  outside. 

White  Spanish. —  This  is  described  by  Keitt  as 
follows :  "  Very  irregularly  shaped,  a  few  being  large, 
smooth  and  roundish ;  but  the  majority  being  long  and 
stringy.  They  have  a  perfectly  white  flesh  and  white 
skin.  They  are  not  prolific,  but  make  a  heavy  growth 
of  vines."  ^ 

White  Yam  ok  White  Belmont. —  This  variety  is 
very  hardy,  is  a  big  yielder,  is  unusually  sweet  for  a 
white  potato,  and  is  largely  used  for  stock-food.  The 
vine  growth  has  been  described  as  follows :  "  Stem 
branching,   rather  bushy  and  very  thick;   light  green 

iT.  C.  Johnson,  Va.  Truck  Exp.  Sta. 

2  S.  C.  Exp.  Sta.,  Bull.  14G. 

ST.  E.  Koitt,  8.  C.  Exp.  Sta.,  Bull.  14G,  p.  C. 


Varieties  135 

below  surface  and  dull  deep  red  above  surface  of  ground. 
Leaves  heart  shaped,  pointed ;  margins  entire ;  deep 
green  upper  surface,  gray  green  lower  surface;  veins 
prominent,  green  color,  medium  size;  petioles  short, 
dull  green."  ^ 

Yellow  Baebadoes. —  This  potato  has  sweet  soft 
flesh  very  much  like  the  Jewel  yam.  The  roots  are 
noticeable  by  their  very  prominent  veins.  The  roots 
are  yellow  inside  and  out,  differing  in  this  respect  from 
the  Wliite  Barbadoes  which,  although  possessing  a  yel- 
low skin,  has  whitish  flesh. 

Yellow  Belmont. —  This  potato,  which  has  been 
illustrated  in  various  publications  as  a  distinct  variety, 
seems  very  closely  allied  if  not  identical  with  the  Yellow 
Nansemond  or  Yellow  Jersey.  It  is  yellow  inside  and 
out  and  has  a  rather  dry  mealy  texture.  The  tubers 
resemble  the  Small  Stem  Jersey  more  closely  than  the 
Big  Stem,  being  smooth  and  less  veiny  than  the  latter. 
For  all  practical  purposes,  the  Yellow  Belmont  may  be 
considered  a  short  chunky  strain  of  the  Yellow  Jersey. 
(See  Plate  IV.) 

Yellow  N"ansemond. —  The  Nansemond  class  has 
many  subdivisions,  among  which  is  the  Yellow  Nanse- 
mond.  It  is  a  long,  smooth,  tapering  unifonn  yellow 
potato  with  almost  white  flesh.  The  roots,  which  are 
small,  are  borne  in  clusters  prolifically.  The  vines 
and  leaves  are  small. 

Yellow  Steasburg. —  This  is  a  heavy-yielding 
variety  used  largely  for  stock-food.  It  is  not  widely 
grown  and  is  not  known  on  the  markets, 

iT.  C.  Johnson,  Va.  Truck  Exp.  Sta. 


136  The  Sweet  Potato 

Of  all  the  varieties  of  sweet  potatoes  given  above 
(and  there  are  perhaps  a  hundred  more  subspecies), 
only  about  a  dozen  are  important  from  the  market 
standpoint.  The  Jersey  type  is  generally  preferred 
on  the  northern  markets,  though  some  of  the  moist 
fleshed  kinds,  especially  the  Nancy  Hall,  are  being 
rapidly  introduced  into  markets  where  heretofore  a 
prejudice  existed  against  southern  potatoes. 

The  southern  markets  demand  the  moist  fleshed 
variety  or  the  so-called  yam  kinds.  The  Nancy  Hall 
and  the  Porto  Rico  are  the  most  popular  and  widely 
grown  for  the  middle  and  late  markets,  while  the 
Triumph  (a  medium  dry  variety)  is  most  popular  for 
the  extra  early  market. 

When  grown  for  stock-food  only,  the  heaviest  yield- 
ing varieties  such  as  the  Yellow  Strasburg,  Red  Ber- 
muda, White  Belmont  and  Hayman,  should  be  used. 
The  contention  of  some  growers  that  the  high  sugar- 
content  of  some  of  the  lesser  yielding  kinds  will  offset 
the  advantage  of  big  yields  in  fattening  stock  has  not 
been  found  to  hold  true  in  practice. 


CHAPTER  VII 
INSECTS  AFFECTING  SWEET  POTATOES 

It  is  commouly  thought  that  the  sweet  potato  is  not 
aifected  seriously  by  insect  pests.  The  home  garden  or 
small  patch  many  seasons  is  practically  free  from  in- 
sect injury,  but  the  commercial  grower  will  have  to  fight 
several  insect  enemies,  some  of  which  do  millions  of 
dollars'  worth  of  damage  annually  to  the  sweet  potato 
crop.  The  different  sections  of  the  country  have  their 
specific  insect  enemies,  the  southern  states  possessing 
by  far  the  greater  number  and  suffering  much  more 
material  damage  than  the  eastern  and  middle  western 
states. 

Insects  that  affect  the  sweet  potato  plant  are  divided 
into  two  general  classes,  the  biting  or  chewing  insects, 
and  the  sucking  insects.  The  first  class  destroy  parts 
of  the  plant  or  the  tubers  by  gnawing  or  eating,  and 
leave  visible  signs.  The  sucking  insects  obtain  their 
substance  by  sticking  a  small  thread-like  bill  into  the 
plant  and  drawing  the  juices  out  without  leaving  visible 
sig-ns  to  the  natural  eye.  The  first  class,  or  biting  in- 
sects, usually  do  much  more  damage  than  the  sucking 
insects. 

THE    SWEET    POTATO    FLEA-BETBTLE 

{Chcetocnema  conflnis) 

As  soon  as  the  sweet  potato  plants  are  set  in  the  field, 
they  are  often  attacked  by  millions  of  small  brownish- 
'l37 


138  The  Sweet  Potato 

black  flea-beetles.  The  leaves  are  affected  by  having 
channels  eaten  out  in  both  surfaces,  the  work  being 
characteristic  of  this  particular  species  and  quite  dif- 
ferent from  other  flea-beetle  injury.  As  a  result  of 
these  attacks,  many  of  the  loaves  of  the  newly  set  plants 
are  killed  outright;  some  turn  brown  and  partially  de- 
cay. ISTew  leaves  usually  put  out  from  the  stalk  and 
thus  prevent  the  plant  from  dying,  but  this  injury 
checks  the  growth  of  the  plants  to  a  considerable  extent, 
and  in  some  cases  kills  them.  Some  seasons  this  injury 
is  more  serious  than  others,  and  some  authorities  claim 
that  it  is  worse  on  low  land.  It  is  most  serious  on  lands 
that  were  planted  the  previous  year  to  potatoes,  and  the 
first  injury  is  usually  near  hedge-rows,  old  fences,  or 
other  rubbish,  where  the  beetles  have  hibernated  during 
the  winter.  This  beetle  is  about  Mg  inch  long,  thick- 
set, of  a  brownish  color,  and  the  wing-covers  when  seen 
under  the  microscope  are  distinctly  furrowed. 

The  beetles  hibernate  over  winter  in  rubbish  under 
logs,  leaves,  or  other  vegetation,  and  emerge  in  the 
spring,  usually  about  May.  They  mate  as  soon  as  they 
have  fed,  and  after  doing  damage  to  the  young  plants 
that  are  set  in  the  fields  they  usually  disappear  about  the 
middle  of  June.  Very  little  is  known  about  the  early 
stages  of  the  insect,  and  they  have  never  been  found 
on  sweet  potato  plants.  The  larva  most  probabl^y  feeds 
on  the  refuse  of  bindweed  and  morning-glories ;  it  is  a 
slender  white  grub  about  Ys  inch  long.  The  beetles 
appear  in  August,  but  do  not  as  a  rule  feed  on  the 
tough  sweet  potato  plants  at  this  season. 

Many  of  the  beetles  will  be  killed,  if.  when  the  plants 
are  taken  from  the  draw-bed,  they  are  dipped  in  a  solu- 
tion of  arsenate  of  lead  1  pound  to  10  gallons  of  water. 


Insects  Affecting  Sweet  Potatoes  139 

By  combining  this  solution  with  bordeaux  mixture  at 
the  ra«te  of  4-4-50,  it  will  also  serve  as  a  repellant 
and  probably  will  be  more  effective  than  the  plain 
arsenical  dip.  All  plants  should  be  allowed  to  dry 
partially  before  setting  out.  Dipping  the  plants  is 
preferable  to  spraying  as  it  saves  much  time  and  they 
can  be  more  thoroughly  and  evenly  covered  by  this 
method,  and  it  is  also  less  expensive.  Late  planted 
sweet  potatoes  are  less  seriously  injured  than  early  set 
ones.  Sturdy  plants  will  withstand  the  attack  and 
recover  from  the  injury  much  better  than  weak  plants. 

TORTOISE    BEETLES 

One  of  the  commonest  pests  of  sweet  potatoes  is  the 
tortoise  beetle.  There  are  several  species  belonging  to 
the  Chrys'omelida?,  which  are  commonly  known  as  gold- 
bugS  or  leaf -eaters.  They  attack  the  leaves-  of  the  plants 
in  both  the  lai*val  and  adult  stages. 

The  tortoise  beetles  hibernate  over  winter  in  rubbish 
and  trash  of  any  kind  that  affords  them  protection  from 
the  cold.  In  the  early  spring  they  feed  on  the  morn- 
ing-glory, which  is  probably  their  original  host-plant. 
As  soon  as  the  plants  are  set  in  the  fi'eld,  the  beetles 
begin  to  eat  large  round  holes  in  the  leaves  and  so  com- 
pletely riddle  them  that  many  plants  have  to  be  re-set. 
Rarely  are  new  shoots  seriously  eaten  or  the  eggs  de- 
posited on  them.  The  larvse  hatch  during  the  first 
half  of  June  in  Maryland ;  probably  earlier  in  the 
South,  and  somewhat  later  in  the  northern  and  north- 
central  states.  The  larvse  are  very  ugly  and  each  is 
provided  with  a  tail-like  fork  about  as  long  as  the  body. 
Upon  this  fork  is  heaped  the  excrement  and  cast  skins 
of  the  larva,  and  they  are  often  overlooked  or  taken 


140  The  Sweet  Potato 

for  a  bit  of  mud  sticking  to  a  leaf.  This  bulk  borne  on 
the  fork  has  given  them  the  name  of  peddlers.  When 
fully  grown,  the  larva  fastens  itself  to  a  leaf,  its  skin 
splits  along  the  back,  and  the  pupa  is  held  to  the  leaf 
by  its  fork.  About  a  week  or  ten  days  later,  the  adult 
beetle  emerges,  eats  for  a  time  and  then  disappears  from 
the  sweet  potato  patch  until  the  following  spring,  Tt 
doubtless  feeds  on  its  wild  food  plants  until  cooler 
weather  drives  it  into  hibernation. 

The  two-striped  sweet  potato  beetle  (Cassida  bivittata). 

This  species  is  usually  the  most  common  of  the  tor- 
toise beetles  attacking  sweet  potatoes.  The  beetle  is 
pale  or  yellow-brown,  striped  with  black.  The  larva  is 
yellowish-white  with  a  longtitudinal  band  along  the 
back,  on  either  side  of  which  is  a  much  lighter  band. 

The  blach-legged  tortoise  beetle  {Cassida  nigripes). 

This  species  very  closely  resembles  the  golden  tor- 
toise beetle,  but  is  not  so  brilliant  in  color,  is  larger, 
has  black  legs  and  three  black  stripes  on  each  wing- 
cover,  and  is  larger  and  more  readily  seen  than  the 
golden  species.  The  larva  is  a  bright  straw-yellow  with 
two  black  marks  just  back  of  the  head,  and  with  the 
body-spines  tipped  with  black.  As  with  the  adult,  the 
larva  is  much  larger  than  that  of  the  golden  beetle. 
This  larva  causes  more  injury  to  the  plants,  although 
possibly  it  is  not  as  common  as  the  striped  beetle.  The 
eggs  of  the  other  species  are  laid  singly,  while  those  of 
the  black-legged  tortoise  beetle  are  more  or  less  bunched, 
usually  placed  in  rows  of  about  three  dozen.  As  soon 
as  the  larvffi  hatch,  all  being  on  one  plant  or  leaf,  their 


Insects  Affecting  Street  Potatoes 


141 


injury    is    very    noticeable,    certain    plants    being    de- 
voured and  others  not  injured  at  all. 

The  golden  tortoise  beetle  (Coptocycla  bicolor)    (Fig. 
14). 

This  is  one  of  the  commonest  species  and  is  found 
on  morning-glory  and  bindweed  during  practically  the 
whole  summer.  The  beetles  on  first  emerging  are  dull 
orange  with  three  prominent  black  dots  on  each  wing- 


FiGUEE   14. —  The  golden  tortoise  beetle:     a,  adult;    b,  larva;   c, 
faecifork;   d,  pupa   (enlarged). 

cover,  but  a  little  later  they  assume  a  metallic  color, 
shining  like  the  most  brilliant  colored  tinsel,  and  the 
black  spots  are  not  so  conspicuous.  All  the  tortoise 
beetles,  and  particularly  this  species,  have  the  habit 
of  dropping  quickly  to  the  ground  and  feigning  death 
when  the  plant  is  shaken  or  when  they  are  disturbed. 

The  eggs  of  this  beetle  differ  from  those  of  other 
species  in  having  three  spinal  prongs  projecting  from 
the  posterior  margin.     The  larva  is  easily  distinguished 


142  The  Sweet  Potato 

by  being  nearly  concealed  under  the  heavy  load  of  ex- 
crement which  it  supports  on  its  spine.  Usually  it  is 
of  a  dark  brown  color,  being  browner  around  the  edges 
and  a  lighter  shade  along  the  middle.  The  pupa  re- 
sembles the  larva. 

The  mottled  tortoise  beetle  (Coptocycla  signifera). 

This  beetle  is  strikingly  different  from  the  other 
species  in  being  black  marked  with  golden  spots  and 
usually  with  a  band  of  black  extending  across  the 
shoulders  to  the  edge  of  the  transparent  margin  of  the 
wing-covers.  The  larva  is  a  pale  smooth  yellow  during 
its  early  stages,  but  after  the  last  molt  the  color  changes 
to  green,  and  after  the  excrement  is  removed  from  the 
fork  it  is  very  difficult  to  recognize  on  a  green  leaf. 
The  larva  does  not  feed  during  this  last  stage.  The 
pupa  is  also  green,  but  probably  brighter  than  the  larva, 
and  marked  by  a  few  black  bands  around  the  first 
abdominal  spiracles. 

The  argus  tortoise  beetle.  (Chelymorpha  argus). 

This  is  the  largest  of  the  tortoise  beetles,  although 
it  is  not  as  common  as  the  preceding  species.  It  is 
also  injurious  to  several  other  plants,  among  these  being 
raspberry,  horse-radish  and  milkweed.  The  adults  are 
usually  brick-red  in  color  with  six  black  dots  on  the  pro- 
thorax  and  six  on  each  wing-cover  which  is  variable  in 
size  and  color.  The  extension  of  the  wing-covers 
present  in  the  other  tortoise  beetles  is  lacking  in  this 
species.  The  eggs  are  laid  in  a  bunch  supported  by  a 
long  stalk.  When  the  larva  hatch,  they  remain  close 
together  and  very  quickly  defoliate  the  plant.     When 


Insects  Affecting  Sweet  Potatoes  143 

full  grown  the  larvae  average  about  /^  inch.  They  are 
slightly  convex,  of  a  pale  yellowish  color,  marked  with 
mnnerous  dark  brown  tubercles  and  prominent  lateral 
spines.  The  pupa  is  of  a  yellowish  color,  marked  with 
dark   brown   which   in   time   becomes   almost   black. 

Control  of  tortoise  heetles. 

From  the  similarity  of  life -history  and  habits  of 
these  closely  related  species,  their  control  may  l)e  the 
same.  The  adult  beetles  do  the  bulk,  of  the  injury  just 
after  the  plants  are  set.  It  is  advised  that  they  be  dip- 
ped in  arsenate  of  lead  before  setting,  as  for  the  flea- 
beetle.  If  the  beetles  become  serious  in  the  field,  plants 
should  be  sprayed  with  arsenate  of  lead,  4  pounds  to 
50  gallons  of  water.  All  places  of  hibernation,  such  as 
fence-rows,  hedge-rows,  woodlands  and  trash,  should  be 
destroyed  during  the  winter,  as  this  will  kill  many  of 
the  adults  in  hibernation. 

SAW-FLIES.  (Fig  15) 

Probably  the  first  injury  from  saw-flies  was  reported 
from  Ocean  Springs,  Mississippi,  in  1886,  by  C.  V. 
Kiley,^  the  larva  practically  ruining  an  entire  crop  of 
sweet  potatoes.  This  pest  is  very  injurious  in  certain 
seasons,  the  most  damage  probably  being  in  the  southern 
states.  Saw-flies  have  since  been  found  on  sweet  pota- 
toes and  morning-glories  in  Nebraska,  Iowa,  Illinois, 
and  several  other  central  and  eastern  states.  The  in- 
jury from  these  flies  cannot  be  said  to  be  serious,  and 
the  outbreaks  are  more  or  less  sporadic  and  local.  The 
writer,  in  1919,  found  about  a  50  per  cent  defoliage 

1  C.  V.  Rile}',  formerly  of  Bureau  of  Entomology. 


144 


lite  Sweet  I'utato 


FiGXJRE  15. —  The  smaller  sweet  potato  saw-fly  (Schizocerus 
ebenits)  :  a,  h,  larva;  c,  d,  segments  of  larva  showing  spines; 
e,  eggs  deposited  under  leaf;  /,  male  saw-fly;  g,  antenna  of  female 
saw-fly.     All  mucli  enlarged;   c,  d,  greatly  enlarged. 

near  Ocean  Springs,  Mississippi.  Two  species  have 
been  identified  on  sweet  potatoes,  Schizocerus  ebenus 
and  Schizocerus  privahis.  These  insects  usually  com- 
mit their  depredations  in  the  middle  of  the  summer, 
probably  the  first  appearance  being,  in  July.  The  eggs 
are  deposited  on  the  leaves  and  the  larva?  hatching  from 
them  eat  the  leaves  to  a  honey-comb,  the  damage  last- 
ing from  two  to  four  weeks.  These  larva?  are  pale 
green  in  color  with  rows  of  small  dots  or  tubercles  run- 
ning longitudinally  along  the  body.  When  seen 
through  the  microscope,  small  fine  hairs  are  readily 
noticed.     When  saw-flies  become  serious  in  a  field,  an 


Insects  Affecting  Sweet  Potatoes  145 

arsenate  spray  is  advised,  using  4  or  5  pounds  arsenate 
of  lead  to  50  gallons  of  water.  To  make  the  spray  stick 
better  1  pound  of  fish-oil  soap  may  be  used.  This 
should  be  applied  as  soon  as  the  young  larvpe  are  noticed. 
Eiley  succeeded  in  bringing  out  a  number  of  para- 
sites from  the  larva?;  this  is  probably  one  reason  why 
the  insect  does  no  more  damage.  Tt  is  thought  that 
the  parasites,  especially  in  the  southern  states  where  the 
winters  are  mild,  will  partially  if  not  completely  con- 
trol this  pest. 

SWEET   POTATO    WEEVIL    (FigS.    16-23) 

Cylas  formicarius 

Within  the  last  decade,  by  far  the  most  serious  in- 
sect pest  of  sweet  potatoes  has  proven  to  be  the  sweet 
potato  weevil.  While  this  insect  has  been  present  in 
the  United  States  since  about  1879  and  its  ravages  have 
been  noticed  locally  in  Texas,  Louisiana  and  Florida,  yet 
it  was  not  until  the  beginning  of  the  War  when  the  whole 
world  was  looking  to  the  United  States  for  its  food  sup- 
ply that  the  seriousness  of  this  pest  was  recognized. 

In  1917  the  Bureau  of  Entomology  started  investiga- 
tions with  the  idea  of  control  and  in  some  instances 
eradication.  This  insect  was  found  in  Texas,  Louisi- 
ana, Mississippi,  Alabama,  Florida  and  Georgia,  and 
also  our  insular  possessions.  It  is  estimated  that  Texas 
in  1917  raised  $9,000,000  worth  of  sweet  potatoes  and 
suffered  a  loss  of  20  per  cent,  or  $1,800,000.  Louisi- 
ana, with  a  crop  valued  at  $5,000,000  lost  12  per  cent, 
or  $600,000,  and  Florida  with  a  $4,000,000  crop  lost 
$400,000  worth.  Thus  it  will  be  seen  that  the  loss 
in  the  southern  states  is  about  $3,000,000  or  $4,000,- 


146  The  Sweet  Potato 

000.  Fortunately,  this  insect  is  confined  to  the  six 
southern  states  just  named;  in  Texas  about  seventy 
counties  in  the  southeastern  section  are  infested ;  in 
Louisiana  most  of  the  parishes  south  of  Vernon  Parish; 
in  Mississippi,  Hancock  County,  Harrison  County, 
Jackson  County  and  part  of  Pearl  River  County ;  in 
Georgia,  Charlton  County ;  and  in  Florida  a  great 
number  of  counties  down  both  the  east  and  west  coast. 
In  all  of  these  sections  the  weevil  is  found  breeding  the 
year  round  on  potatoes  in  the  field,  the  tubers  in  storage 
and  also  on  certain  species  of  sea-side  morning-glories 
and  some  species  of  bindweed.  Infestation  in  the 
spring  usually  takes  place  through  the  over-wintered 
weevil.  Weevils  may  pass  the  winter  in  three  ways: 
First,  in  storage;  second,  in  roots  left  in  the  ground 
from  volunteers;  third,  in  those  left  through  poor  har- 
vesting. Weevils  in  all  stages  may  be  found  in  buried 
sweet  potatoes  along  the  Coast  during  the  winter.  In 
nearly  all  instances,  infestation  can  be  traced  to  me- 
chanical means  of  transportation.  By  this  is  meant 
the  selling  and  giving  away  of  seed  potatoes,  plants, 
draws  or  vines,  or  in  carelessly  shipping  potatoes  for 
commercial  purposes.  All  sweet  potato  gTowers  or 
dealers  and  the  transportation  companies  should  be 
warned  against  this  danger.  Sweet  potatoes  or  plants 
for  propagation  purposes  should  be  carefully  examined 
before  being  shipped,  and  no  such  material  should  be 
accepted  from  a  weevil-infested  area.  To  meet  such 
conditions,  state  quarantine  regulations  should  be  placed 
in  effect  that  will  compel  the  small  grower  either  to 
take  care  of  his  own  crop  or  to  permit  it  to  be  destroyed 
in  case  of  severe  infestation  of  weevil. 


Insects  Affecting  Sweet  Potatoes 


u: 


While  it  is  not  known  definitely  how  much  cold  this 
insect  can  withstand,  it  is  reasonahle  to  suppose  that 
if  it  should  be  transported  to  the  northern  states  it 
would  be  protected  from  the  cold  winters  by  being- 
housed  with  the  potatoes.  It  is  a  prevailing  opinion 
that  while  the  insects  would  probably  freeze  out  in  the 
fields,  the  protection  given  to  potatoes  in  storage  will 
also  protect  the  weevils  and  perpetuate  them  from  year 
to  year. 

Description. 

The  adult  of  the  sweet  potato  weevil  is  a  snout  beetle 
of  an  ant-like  appearance,  about  Vi  inch  long,  with 
metallic  blue  wing-cov- 
ers, the  thorax  brick 
red,  head  dark  blue,  and 
the  legs  brick  red.  The 
antenna  are  long  and 
have  clubs  at  the  end. 
The  male  bears  the 
longer  larger  club,  thus 
distinguishing  him 

from  the  female.  The 
eggs  are  pale  yellow, 
partially  oval,  and 
somewhat  narrowed  at 
the  end  which  is  at- 
tached to  the  potato. 
The  surface  is  not  shining  or  polished,  but  is  gi*anu- 
lated.  The  length  is  about  Mo  of  an  inch.  The  larva 
when  full  grown  is  cylindrical  and  robust ;  the  segments 
are    permanent    and    rounded,    color   practically    pure 


Figure    16. —  The    sweet    potato 
weevil :     Adult,  greatly  enlarged. 


148 


The  Sweet  Potato 


white ;  head  pale  brown ; 
mouth-parts  a  brownish 
shade ;  a  few  delicate  hairs 
can  be  seen  under  the  micro- 
scope. The  larva  is  legless, 
although  very  thick  leg  pads 
are  apparent  (see  Fig.  17). 
The  length  when  grown  is 
about  %  of  an  inch.  Tho 
pupa  is  at  first  the  same  color 
as  the  larva,  but  before  trans- 
formation to  the  adult  be- 
comes considerably  darker. 
The  wing  pads  are  short  and 
narrow,  folded,  over  the  un- 
der side  of  the  body;  the 
head  and  back  fold  down 
upon  the  breast ;  on  the  head 
are  several  small  tubercles, 
e'ach  one  bearing  a  slender  spine;  it  is  about  %  of  an 
inch  long.  The  pupa  is  not  active,  not  partaking  of 
food.  The  lower  half  of  the  body  is  mobile,  enabling 
the  p^ipa  to  turn  about  in  its  burrow  or  pupa  case. 


b 

Figure  17. —  Tlie  sweet 
potato  weevil:  a,  larva;  ft, 
dorsal  and  ventral  views  of 
pupa.     Enlarged. 


Life  history. 

While  it  is  thought  that  the  sweet  potato  weevil  passes 
through  a  part  of  the  winter  in  hibernation,  it  is  active 
throughout  the  entire  year  in  the  Gulf  states.  Eggs, 
larva^,  pupa?  and  adults  may  be  found  throughout  the 
winter  over  its  entire  range.  ^^  ^ 


Insects  Affecting  Sweet  Potatoes 


149 


Figure    18. —  Present   known   distribution   of   the  sweet  potato 
weevil  in  tlie  southern  United  States. 


From  observations  made  by  authorities,  very  little 
egg-laying  takes  place  during  the  winter,  but  the  adults 
are  active  on  warm  days  and  are  frequently  found 
crawling  about  and  feeding  on  stored  potatoes.  In 
the  spring  and  in  the  field  the  beetles  become  much 


PiGURE  19. — ■  Sweet  potato,  nearly  fresh,  showing  exit  holes  and 
feeding  punctures  of  sweet  potato  weevil  toward  stem.  Note  outer 
end  scarcely  attacked.     Sample  from  Louisiana. 


150  The  Sweet  Potato 

more  active.  Frequently  potatoes  in  storage  that  have 
been  little  affected  during  the  winter  may  be  entirely 
riddled  in  the  two  spring  months.  In  the  field  or  draw- 
bed,  the  beetles  first  feed  on  leaves  and  the  stems  of 


Figure  20. —  Sweet  potato  badly  infested  by  sweet  potato  M'eevil, 
decidedly  dry,  but  sliowiiifr  break  at  middle  where  living  larvae, 
pupae,  and  adults  were  found.     Somewhat  reduced. 

the  young  plants,  eating  or  gnawing  irregular  holes 
and  excavations  in  them.  After  the  plants  reach  a 
sufficient  size  to  become  woody,  the  eggs  are  deposited 
on  the  stem  near  the  surface  of  the  ground.  If  the 
ground  is  loose  or  cracked  from  the  baking  sun,  the 
female  will  follow  the  vine  down  as  far  as  possible  and 
deposit  her  eggs  there.  If  the  tubers  themselves  are 
exposed  to  the  surface,  eggs  are  usually  deposited  on 
them.  The  young  larva  eats  into  the  potato,  leaving 
an  irregular  tunnel  or  furrow  filled  with  excrement. 
They  burrow  and  feed  throughout  the  winter  until 
their  full  growth  is  reached,  when  they  form  an  oval 
cavity  or  pupal  cell,  usually  near  the  surface  of  the 
potato,  in  which  they  pupate.  In  cases  in  which  the 
eggs  are  deposited  on  the  vines  in  the -field,  the  larvse 
bore  down  the  stem  until  they  reach  the  potato  and 


Insects  Affecting  Sweet  Potatoes  151 

enter  it.  In  this  way  the  upper  portion  or  the  end 
attached  to  the  vine  is  always  attacked  first.  After  the 
beetles    emerge   from   pupation,    thej   break    irregular 


£^r 

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^^ 

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SI^^^S'^Ff^K^^sl 

V  gi)^BW.«jgjWBtwfa^<j 

iKfW^^i^i^S^^W 

\^^^^^^^^^^a 

fm^^'^-'i^^S 

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Figure  21. —  Cross-section  of  sweet  potato  showing  injury  by 
sweet  potato  weevil.  Larva  in  burrow  at  top;  pupa  below; 
opening   to   tunnels   elsewhere.     Enlarged   three    diameters. 

openings  in  the  skin  of  the  potato  which  are  much 
larger  than  either  feeding  or  egg  punctures.  As  the 
attacks  progress  and  the  infestation  becomes  serious, 
especially  if  in  storage,  the  tubers  develop  a  tendency 
to  dry  out  and  shrivel.  In  some  cases  of  excessive  mois- 
ture or  being  bruised,  the  potatoes  are  affected  with 
brown-rot  and  often  decay,  causing  the  death  of  the 
weevils.  If  the  potatoes  become  extraordinarily  hard 
and  dry,  the  newly  emerged  adults  cannot  push  their 
way  to  the  surface  and  are  thus  confined  in  their  cells 
and  die. 

M.  M,  High,^  who  has  been  investigating  the  weevil 
1  Farmers'  Bull.,  U.  S.  Dept.  Agr. 


152 


The  Sweet  Potato 


in  south  Texas,  gives  the  following  figures  in  reference 
to  the  life  history:  A  single  female  has  been  known 
to  deposit  more  than  300  eggs,  as  many  as  ten  in  a 
single  night,  the  process  of  laying  a  single  egg  being 


Figure  22. —  Sweet  potato  beginning  to  dry,  showing  punctures 
made  by  the  swoet  potato  weevil,  chiefly  for  food.  Interior  highly 
infested  and  root  much  shrunken. 


quite  protracted.  The  eggs  are  not  laid  in  feeding 
punctures  but  in  cavities  bored  especially  for  them. 
These  holes  are  usually  at  an  angle  of  about  sixty  de- 
grees, while  the  feeding  punctures  are  practically  per- 
pendicular. Transformation  from  eg^  to  adult  lasts, 
in  warm  weather,  about  thirty  days,  and  in  cooler 
weather  as  many  as  forty-two  days,  or  a  longer  length 
of  time,  varying  with  temperature.  The  pupa  period 
lasts  eight  or  ten  days ;  the  egg  four  to  eight,  and  the 
larva  or  feeding  stage  from  fourteen  to  twenty-eight 
days. 

Conirol. 

The  sweet  potato  weevil  breeds  exclusively  on  sweet 
potato  and  closely  related   plants,   and  although   it   is 


Insects  Affecting  Sweet  Potatoes  153 

provided  with  perfectly  developed  wings,  it  seldom  is 
seen  in  flight  and  this  method  of  spreading  may  be  dis- 
regarded. Therefore,  it  must  be  assumed  that  the 
weevil  can  be  controlled  or  held  to  a  specified  infestation 
by  care  in  the  transportation  of  sweet  potatoes  and  by- 
products. It  is  possible  that  the  weevil  will  crawl  for 
a  great  distance;  this  being  recognized,  growers  a  few 
miles  from  infested  farms  need  have  very  little  fear 
of  damage  provided  they  take  ordinary  precautions. 

Clean  culture  is  the  chief  ally  in  fighting  the  weevil. 
The  ground  should  be  kept  clean  at  all  times,  plants 
healthy  and  in  good  growing  condition,  and  the  land 
should  not  be  allowed  to  bake  or  crack  open  during  the 
summer.  It  is  further  recommended  that  the  crop  be 
put  out  later  and  harvested  earlier  than  is  usually  the 
practice.  This  gives  a  shorter  season  for  the  plants 
and  tubers  to  become  infested  in  the  field.  At  har- 
vest time  sweet  potatoes  should  be  divided  into  three 
lots:  Weevil-free  tubers;  tubers  slightly  infested; 
tubers  badly  infested.  The  last  lot  should  immediately 
be  fed  to  the  cattle  or  poultry  after  cooking,  or  should 
be  burned.  The  second  lot  may  be  fumigated  for  im- 
mediate use ;  and  the  first  stored  for  winter  keeping. 
In  this  manner  no  direct  loss  will  result  from  the  in- 
fested potatoes,  as  they  make  valuable  stock-feed.  As 
soon  as  the  potatoes  are  removed  from  the  field,  the 
vines  should  be  raked  into  piles  and  burned,  as  soon 
as  dry.  Hogs  should  be  turned  into  the  field  to  eat 
all  the  small  stringy  potatoes  and  cut  ones  that  are  left. 
In  this  way  tubers  that  might  remain  in  the  field  during 
the  winter  will  be  destroyed,  and  the  field  will  prob- 
ably be  freed  of  over-wintering  weevils. 


154 


The  Sweet  Potato 


FiGTJRE  23. —  Corner  of  a  va- 
cant lot  in  Florida  showing  mat 
of  wild  sweet  potato  vines  badly 
infested  with  the  sweet  potato 
weevil. 


It  is  not  advisable  that  potatoes  be  planted  to  the 
same  land  two  years  in  succession.     The  crop  for  this 

year  should  be  put  as  far 
as  possible  from  last 
year's  field.  When  the 
seed-bed  is  used,  it  is  ad- 
vised that  the  young 
plants  be  sprayed  once  or 
twice  with  arsenate  of 
lead,  4  pounds  to  50  gal- 
lons of  water.  Time 
may  be  saved  by  dipping 
the  plants  as  they  are 
pulled  from  the  draw-bed.  Some  of  the  weevils  while 
feeding  on  the  young  plants  will  be  killed.  This  will 
effect  a  partial  control  in  the  field. 

So  far  as  is  known,  no  variety  of  potatoes  is  immune 
from  the  attack,  although  sweeter  yellow  varieties 
knovm  in  the  South  as  yams  are  preferred,  the  Nancy 
Hall  variety  being  one  of  the  favorites. 

It  is  especially  advised  in  order  to  eradicate  this  in- 
sect from  the  farm  that  no  seed  potato  bed  be  put  out, 
but  that  plants  be  bought  from  some  reliable  dealer 
or  firm  that  have  had  their  plants  inspected  and  tagged 
by  a  state  official,  certifying  that  they  are  free  from  all 
insect  pests  or  plant  diseases. 

In  the  spring,  as  soon  as  the  main  stock  of  edible 
potatoes  has  been  disposed  of,  the  old  store-house  or 
bin  should  be  cleaned  up  thoroughly.  In  this  way  sev- 
eral weeks  should  elapse  between  the.  date  of  cleaning  up 
and  that  of  setting  out  new  plants.  If  any  adulti 
weevils  should  be  left,  it  is  believed  that  they  will  be 
starved  before  this  new  food  supply  is  brought  in. 


CHAPTER  VIII 
DISEASES  OF  THE  SWEET  POTATO 

The  sweet  potato  grower  has  to  contend  with  com- 
paratively few  diseases  that  covild  not  be  prevented  or 
cured  if  a  little  time  and  labor  were  expended.  The 
small  farmer  is  chiefly  troubled  by  storage  rots,  while 
the  large  grower,  who  has  a  dry  house  which  will  largely 
prevent  these  rots,  will  have  to  fight  diseases  in  the 
field. 

The  practice  of  selling  in  the  fall  as  soon  as  pota- 
toes are  harvested  has  been  brought  about  by  the  con- 
ditions prevailing  in  the  "  bank  "  or  "  pit."  Farmers 
have  been  accustomed  to  rush  their  product  on  the 
market  before  the  fatal  rot  sets  in.  It  is  estimated  that 
only  about  50  per  cent  of  the  potatoes  produced  are 
consumed ;  the  other  50  per  cent  decaying  from  some 
one  of  the  storage  rots. 

In  the  field  some  of  the  diseases  can  be  destroyed  by 
spraying,  but  in  certain  cases  crop  rotation,  change  of 
seed  or  draws  and  good  cultural  methods  are  the  only 
control  measures  that  can  be  advised. 

The  sweet  potato  troubles  may  be  divided  into  the 
following  general  classes:  Seed  and  draw-bed;  field 
diseases,  of  tuber,  stems  and  leaves ;  storage  rots ;  decay 
from  mechanical  causes  as  age,  frost,  excessive  heat  and 
cold,  handling  at  harvest,  culling  and  grading  for  ship- 
ment. 

155 


156  The  Sweet  Potato 

STEM-EOT  (wilt,  blue-stem)   (Plate  V) 

Stem-rot,  caused  by  the  fungi  Fusariuni  batatatis  and 
F.  hyperoxysporum,  varies  somewhat  in  appearance  with 
different  varieties.  The  first  indication  of  the  disease 
in  the  field  is  the  dull  color  of  tke  leaves  affected.  They 
finally  become  yellowed  between  the  veins  and  some- 
what distorted,  these  symptoms  being  followed  by  wilt- 
ing. On  pinching  open  the  stem  of  a  diseased  plant, 
it  will  be  found  to  be  blackened  inside.  This  discolora- 
tion sometimes  extends  several  feet  from  the  hill. 
Later  the  surface  of  the  stem  roughens  and  ruptures 
and  becomes  blackened  and  rotted.  The  organism  that 
causes  stem-rot  may  also  attack  the  roots,  forming  a 
blackened  ring  about  %  inch  beneath  the  surface.  If 
such  potatoes  are  used  for  seed,  diseased  sprouts  are 
likely  to  be  developed  therefrom. 

In  the  seed-bed,  the  symptoms  of  the  disease  are 
similar  to  those  in  the  field.  Diseased  draws  can  be 
detected  by  the  faint  discoloration  of  the  foliage  and 
the  purplish  tint  in  the  tender  white  stem. 

Stem-rot  is  know  to  be  prevalent  in  N^ew  Jersey, 
Delaware,  Maryland,  Virginia,  Illinois,  Iowa,  Kansas, 
Alabama,  and  Arkansas,  and  to  be  present  in  Missouri, 
North  Carolina,  Ohio,  Georgia,  Texas,  Oklahoma,  and 
]\Iississippi.  It  is  probable  that  the  disease  occurs  in 
other  states  also.  In  some  sections  the  disease  is  at 
present  relatively  unimportant,  owing  to  the  fact  that 
varieties  have  been  grown  which  are  somewhat  resis- 
tant to  it  or  that  the  sweet  potato  industry  is  compar- 
atively new  and  the  disease  has  not  yet  become  serious. 

It  is  not  definitely  known  how  long  the  stem-rot 
fungus  will  live   in  the  soil  in  the  absence  of  sweet 


Diseases  of  the  Sweet  Potato  157, 

potatoes,  but  probably  for  several  years.  For  that  rea- 
son, sweet  potatoes  should  not  be  planted  on  the  same 
ground  oftener  than  once  in  three  or  four  years.  It  is 
very  doubtful  whether  that  length  of  time  will  com- 
pletely eradicate  the  fungus,  but  it  certainly  will 
greatly  reduce  it.  No  other  crops  are  known  to  be 
attacked  by  the  stem-rot  fungus;  therefore,  any  crops 
commonly  grown  in  the  region  may  be  used  in  the  ro- 
tation. 

It  is  important  that  all  seed  potatoes  and  commer- 
cially grown  draws  should  come  from  reliable  dealers 
and  accompanied  by  a  certifica-te  stating  that  the  po- 
tatoes or  draws  are  free  from  all  serious  diseases. 

Control  of  stemrvot. 

As  has  already  been  pointed  out,  the  fungus  invades 
the  potato.  Consequently  if  diseased  potatoes  are 
bedded  out,  diseased  sprouts  or  draws  may  be  expected, 
as  the  fungus  will  pass  from  the  tuber  to  the  stem  of 
the  young  plant.  In  the  early  stages  these  diseased 
plants  are  hard  to  detect,  and  many  will  be  set  out  in 
the  field  where  the  growth  of  the  fungus  will  continue. 
In  the  spring  the  seed  potatoes  should  be  disinfected 
just  before  bedding  by  treating  for  five  to  ten  minutes 
in  a  solution  made  by  dissolving  1  ounce  of  corrosive 
sublimate  in  8  gallons  of  water.  Only  wooden  ves- 
sels should  be  used  for  disinfection.  Corrosive  sub- 
limate is  a  strong  poison  and  should  be  kept  out  of  the 
reach  of  animals.  After  the  potatoes  are  disinfected 
they  should  be  rinsed  in  pure  water  and  laid  in  the 
sun  to  dry.  This  treatment  will  not  kill  the  stem-rot 
fungus  within  the  potato,  but  it  will  destroy  any  spores 
that  may  be  on  the  surface.     The  solution  of  corrosive 


168  The  Sweet  Potato 

sublimate  should  not  be  used  more  than  two  or  three 
times,  since  it  loses  its  effectiveness  after  repeated  use. 
If  for  any  reason  corrosive  sublimate  can  not  be  used, 
the  potatoes  may  be  immersed  for  five  minutes  in  a  solu- 
tion of  formaldehyde  made  by  adding  1  pint  of  com- 
mercial formalin  to  30  gallons  of  water.  They  should 
be  rinsed  in  water  and  dried  before  bedding. 

The  continued  use  of  the  same  soil  for  the  seed-bed 
year  after  year  is  the  chief  source  of  many  of  the  dis- 
eases of  sweet  potatoes.  A  change  of  bedding  soil  or 
ground  should  be  practiced  each  year.  In  fact,  clean 
sand  hauled  in  from  the  woods  is  one  of  the  best  ma- 
terials to  use  in  the  bed.  Stable  manure  is  not  essen- 
tial to  the  production  of  healthy  draws  and  is  much 
more  likely  to  become  infected  with  disease  germs  than 
this  fresh  new  sand.  Many  farmers  throw  aside  the 
diseased  potatoes  as  they  bed  down  the  good  ones ;  fowls 
or  dogs  running  loose  around  the  place  will  easily  take 
the  disease  to  the  bed  on  their  feet.  All  such  careless- 
ness should  be  strictly  avoided. 

FOOT-ROT  (Plates  VI  and  VII) 
(Plenodomus  destruens) 

Of  the  various  diseases  to  which  the  sweet  potato  is 
subject,  foot-rot  (die-off)  is  one  of  the  most  serious. 
In  the  field,  foot-rot  first  manifests  itself  as  dark  spots 
or  areas  at  the  base  of  the  stem.  The  diseased  areas 
may  extend  from  1  to  5  or  6  inches  up  the  stem,  the 
remainder  appearing  more  or  less  normal.  The  tissues 
within  the  diseased  area  of  the  stem  are  killed  and  the 
fruiting  bodies  of  fungus  develop  below  the  surface. 
The  woody  part  of  the  stem  becomes  blackened  and 


Plate  VI. —  Sweet  potato  foot-rot.  a.  The  lower  part  of  a 
sweet  potato  plant  killed  by  the  foot-rot  fungus,  b,  A  sweet 
potato  rotted  by  the  foot-rot  fungus.  Note  the  fruiting  bodies 
crowded  together  over  the  surface. 


Diseases  of  the  Sweet  Potato  159 

dried  out.  In  the  seed-bed,  tlie  young  sprouts  shrivel 
and  turn  black  near  the  surface  of  the  ground  extend- 
ing a  few  inches  up  the  stem.  The  young  draws  look 
weak  and  discolored  and  finally  die  in  severe  cases. 
The  tubers  are  usually  attacked  from  one  end  and 
shrivel  and  dry  up,  the  disease  gradually  working  back 
toward  the  other  end. 

Foot-rot  is  distributed  in  the  same  way  as  stem-rot 
and  black-rot,  through  diseased  soil,  exchange  of  plants 
or  seed  potatoes. 

Foot-rot  is  known  in  Virginia,  Iowa,  and  Missouri, 
and  it  is  probable  that  it  occurs' elsewhere. 

Owing  to  the  fact  that  it  is  not  so  widely  distrib- 
uted, the  total  loss  that  may  be  attributed  to  this  disease 
is  much  less  than  with  black-rot  and  stem-rot.  In  lo- 
calities where  it  does  occur,  however,  it  produces 
greater  loss  than  either  of  those  diseases.  In  certain 
sections  of  Virginia,  Ohio,  and  Iowa,  it  has  been  esti- 
mated to  produce  a  loss  of  50  per  cent  of  the  crop  in 
one  year. 

The  same  control  measures  should  be  applied  for  this 
disease  as  for  stem-rot  and  black-rot :  —  namely,  seed 
selection,  clean  seed-beds,  and  crop  rotation. 

ROOT-ROT  (Plate  VII) 

(Ozonium  omnivorum) 

This  disease  is  best  known  as  the  Texas  root-rot  of 
cotton  and  alfalfa.  The  causal  organism  gains  access 
to  the  plants  on  the  underground  parts  and  spreads  in 
both  directions,  invading  the  vines  for  6  to  12  inches 
above  the  ground.  It  may  enter  the  potato  at  the  end 
or  form  lesions  of  varying  sizes  on  the  surface.     In 


160  Tlie  Sweet  Putalo 

either  case  a  firm  brown  rot  is  produced,  resulting  in  the 
complete  destruction  of  the  potato  (Plate  VII).  Above 
ground  the  growth  is  within  the  stem  and  may  be  de- 
tected by  the  brown  discoloration  produced.  The  or- 
ganism lives  from  one  season  to  the  next  in  the  soil  on 
dead  vegetable  matter,  or  in  the  far  South  probably  on 
growing  winter  crops.  It  is  killed  by  hard  freezing, 
and  this  alone  probably  restricts  the  fungus  to  the 
southern  states. 

Eoot-rot,  so  far  as  known,  occurs  only  in  Texas, 
New  Mexico,  Oklahoma,  and  Arizona.  When  the  dis- 
ease once  gets  into  a  field,  a  whole  crop  may  be  de- 
stroyed. Large  fields  have  been  seen  in  which  not  more 
than  10  per  cent  of  a  crop  was  produced.  Viewed 
from  a  distance,  the  fields  looked  promising,  but  when 
harvested  the  potatoes  were  nearly  all  found  to  be 
destroyed  by  the  fungus. 

While  it  may  now  be  considered  a  southwestern  dis- 
ease, it  may  be  expected  to  spread  to  the  eastern,  south- 
eastern, and  northern  states,  if  rigid  inspection  and 
quarantine  measures  are  not  observed. 

Root-rot  is  worse  on  heavy  soils  and  potatoes  should 
be  planted  on  light  well-drained  soil.  The  disease  has 
a  great  variety  of  host  plants  and  is  particularly  hard 
to  control  on  this  account.  Deep,  clean  cultivation  and 
crop  rotation  are  essential.  Disease-free  seed  should 
be  selected,  a  rotation  practiced  with  corn  or  other 
cereals  as  the  disease  is  not  known  to  attack  these  crops. 

BLACK-KOT    (bLACK-STIANk)     (PlatCS  V,   VII) 

(Sphaeronema  fimbriatum) 
Black-rot  may  occur  on  any  of  the  undergTound  parts 
of   a   plant.     The   disease   is   characterized   by   nearly 


Diseases  of  the  Sweet  Potato  161 

black,  sunken,  circular  spots  on  the  surface.  In  the 
early  stages  the  spots  appear  as  nearly  round,  but  they 
become  larger  and  lose  their  shape  somewhat.  Fre- 
quently nearly  the  whole  of  a  potato  is  covered  by  this 
disease.  The  tissues  beneath  the  surface  have  a  green- 
ish tint,  while  the  surface  of  the  spot  itself  is  often 
metallic  in  luster.  On  the  plants  the  disease  begins  as 
small  round  spots  and  continues  to  grow  until  the  whole 
stem  of  the  plant  is  rotted  off.  Frequently  it  extends 
up  the  stem  to  the  surface  of  the  soil  but  never  above. 

Black-rot  was  reported  the  first  time  in  1890  in  New 
Jersey,  but  it  is  probable  that  it  occurred  long  before 
that.  Since  then  it  has  been  found  in  practically  every 
part  of  the  United  States  where  sweet  potatoes  are 
grown  and  also  in  the  West  Indies  and  New  Zealand. 

The  disease  is  known  in  New  Jersey,  Delaware, 
Maryland,  Virginia,  Ohio,  Illinois,  Missouri,  Iowa,  Ok- 
lahoma, Texas,  Arkansas,  North  Carolina,  South  Car- 
olina, Georgia,  and  Alabama,  and  it  is  possible  that 
it  occurs  wherever  sweet  potatoes  are  grown.  Black- 
rot  has  been  found  on  the  following  varieties:  Nancy 
Hall,  Yellow  Jersey,  Big-Stem  Jersey,  Red  Beraiuda, 
Miles  Yam,  White  Yam,  Southern  Queen,  Pierson, 
Early  Red  Carolina,  Florida,  Yellow  Strasburg,  Key 
West  Yam,  Red  Jersey,  Dahomey,  Red  Brazilian,  Yel- 
low Yam,  Vineless  Yam,  and  Georgia. 

In  all  the  regions  mentioned,  the  disease  is  preva- 
lent on  the  plants  or  slips  in  the  hotbed  and  on  the 
potatoes  in  the  storage-houses  in  the  winter;  in  fact, 
heavy  losses  are  caused  by  this  disease  in  storage-houses, 
where  it  develops  freely  under  favorable  conditions  and 
renders  the  potatoes  unfit  for  consumption. 

The  same  control  methods  in  general  should  be  ap- 


162  The  Sweet  Potato 

plied  to  black-rot  as  to  stem-rot,  particularly  the  prepa- 
ration of  the  hotbed.  If  black-rot  alone  is  concerned, 
the  seed  may  be  selected  in  the  spring  instead  of  in  the 
fall.  If  selected  in  the  fall,  it  should  be  picked  over 
again  in  the  spring  and  any  potatoes  with  suspicious 
spots  on  them  discarded. 

The  treatment  of  the  soil  with  sulfur,  lime,  gypsum, 
or  different  fertilizers  has  little  or  no  effect  on  the  dis- 
ease. Dipping  the  slips  in  a  solution  of  bordeaux  mix- 
ture or  in  a  lime-sulfur  mixture  just  before  setting 
them  in  the  field  does  not  prevent  the  disease,  but  has 
been  found  greatly  to  injure  the  plants. 

SCURF  (soil-stain,  soil-splotcii,  bust,  jersey  mark) 

Scurf  is  characterized  by  a  brown  discoloration  of  the 
surface  of  the  underground  parts  of  the  sweet  potato 
plant.  (Plates  V,  VII.)  The  discolored  areas  may 
take  the  form  of  spots  of  varying  sizes  and  shapes  with 
no  definite  outline  or  there  may  be  a  uniform  rusting  of 
the  entire  surface  of  the  potato.  The  scurf  produces  no 
rupture  of  the  sweet  potato  and  is  so  superficial  as  to 
be  scraped  off  easily  by  the  finger-nail. 

Scurf  is  widely  spread  over  the  sweet  potato  area. 

To  control  this  disease,  the  seed  potatoes  should  be 
disinfected  for  ten  minutes  in  a  solution  made  by  dis- 
solving 1  ounce  of  mercuric  chlorid  (corrosive  subli- 
mate) in  8  gallons  of  water.  They  should  then  be 
dipped  in  water  and  dried.  Soil  or  sand  obtained  from 
the  woods  or  from  fields  where  sweet  potatoes  have  never 
been  grown  should  be  used  in  the  hotbed.  The  plants 
should  be  set  in  new  ground  or  ground  never  before 
employed  for  sweet  potatoes. 

Scurf  is  worse  on  heavv  soils  and  on  those  contain- 


Diseases  of  the  Sweet  Potato  163 

ing  a  large  quantity  of  organic  matter,  such  as  manure. 
Such  soils  should  be  avoided.  It  is  likewise  more  se- 
rious during  a  wet  season  and  on  low  wet  ground.  The 
treatment  of  the  soil  with  fungicides  or  fertilizers  has 
not  been  effective  as  a  means  of  control. 

LEAF-BLIOHT   (Plate  VIII) 

(PhyUosticta  hatatas) 

Leaf-blight  appears  on  the  upper  side  of  the  leaves, 
either  as  roundish  or  angular  spots.  These  varv  in  size 
from  Ys  to  Yo  inch  in  diameter  and  are  defined  bv  a 
distinct  line  around  them.  Within  the  spot  are  several 
blotches  or  dark  patches  which  are  caused  by  the  spores 
of  the  disease.  So  far  it  is  not  known  that  this  disease 
is  parasitic  on  any  other  plant  and  only  on  the  leaves  of 
potatoes.  It  is  thought  to  live  over  the  winter  on  the 
dead  leaves.  The  disease  usually  manifests  itself  on 
the  mature  leaves. 

Leaf-blight  occurs  principally  in  the  southern  states, 
rarely  appearing  on  the  east  coast  north  of  Virginia, 
or  in  Iowa,  Illinois,  and  Kansas.  So  far  the  disease  has 
not  been  of  enough  consequence  to  justify  treatment. 

LEAF-SPOT  (Plate  VIII) 

{Septorid  bataticola) 

This  fungus  is  similar  in  general  appearance  to  leaf- 
blight.  It  manifests  itself  in  the  form  of  spots  Ys  to  Y-t 
inch  in  diameter ;  these  spots  are  scattered  promiscuously 
over  the  foliage.  They  are  white  surrounded  by  a 
brown  border.  In  the  center  of  these  spots  -are  dark 
areas  very  similar  to  the  ones  described  in  leaf-blight. 
These  are  the  clusters  of  spores  before  they  are  released 


164  The  Sweet  Potato 

to  scatter  to  other  sections  of  the  leaves.  This  disease  is 
not  known  on  other  host  plants  and  only  on  the  leaves 
of  the  sweet  potato  plant.  It  probably  winters  on  the 
dead  leaves,  and  may  be  transmitted  by  insects,  wind, 
or  rain. 

Leaf-spot  is  widely  distributed,  having  been  collected 
from  the  eastern  coast  and  also  from  the  states  of 
Iowa  and  Illinois.  This  disease  has  never  been  known 
to  be  serious;  no  remedies  are  required. 

WHITE-RUST    (leaf-mold) 

(Albugo  ipomcece-paTidurance) 

The  first  symptom  of  white-rust  is  a  loss  of  the  green 
color  in  the  indefinite  spots  on  the  under  side  of  the 
leaf.  (Plate  VIII.)  Later  these  spots  become  brown 
and  covered  with  a  whitish  viscid  growth,  which  is  fi- 
nally more  or  less  powdery.  This  white  powdery  mass 
is  made  up  of  numerous  spores  or  reproductive  bodies, 
which  serve  to  start  a  new  infection  if  they  fall  on  an- 
other leaf  and  conditions  are  favorable,  such  as  high 
temperature  and  relatively  high  humidity.  Frequent 
rains  and  heavy  dews  are  favorable  to  the  spread  of  this 
disease.  No  great  harm  results  from  the  attack  of  this 
fungus,  although  it  may  sometimes  produce  swellings  on 
the  stems  and  petioles  and  malformations  of  the  leaves. 
White-rust  is  much  more  prevalent  in  wot  weather.  It 
is  widely  spread,  having  been  found  in  both  the  eastern 
and  the  central  section. 


Diseases  of  the  Sweet  Potato  165 

soFT-EOT  (Plate  V) 
(RJiizopus  nigricans) 

Soft-rot  is  the  most  destructive  of  the  storage 
diseases ;  in  fact,  it  is  claimed  by  many  to  be  more  in- 
jurious than  all  others  combined.  This  is  the  bread- 
mold  which  is  so  common  everywhere.  The  decay  be- 
gins at  one  end  of  the  potato  or  at  a  cut  or  bruise  and 
spreads  rapidly  throughout  the  whole  of  the  tuber, 
a  day  or  so  being  long  enough  under  high  temperature 
and  humidity.  Soft-rot  sets  in  soon  after  the  potatoes 
are  harvested  and  stored  and  continues  more  or  less 
throughout  the  fall  and  winter  season.  As  long  as  the 
skin  of  the  potato  remains  unbroken,  the  fungus  does 
not  ordinarily  produce  spores ;  but  in  the  presence  of  a 
cut  or  bruise,  fruiting  stalks  are  pushed  up  and  thou- 
sands of  spores  are  produced.  As  soon  as  these  come  in 
contact  with  the  other  potatoes,  the  trouble  begins. 
They  may  be  spread  by  insects,  wind  or  rain. 

Owing  to  the  abundance  of  the  spores  of  this  fungus, 
little  can  be  done  to  control  it  except  careful  handling 
of  tubers  at  harvest.  Potatoes  should  not  be  put  on 
heavy  poorly  drained  soil. 

RING-ROT  (Plate  VII) 

(Rhizopus  nigricans) 

Ring-rot  is  caused  by  the  same  mold  as  soft-rot.  The 
two  diseases  are  very  similar  except  that  ring-rot  attacks 
the  potato  nearer  the  middle  instead  of  the  end  and 
forms  a  distinct  ring  around  the  tuber.  This  ring 
varies  in  width  from  about  1  to  3  inches.  In  high  tem- 
perature and  humidity,  the  whole  potato  may  often  be 


166  The  Sweet  Potato 

destroyed.     The  same  precautions  should  be  used  for 
this  form  of  the  disease  as  for  soft-rot. 

DEY-EOT  (Plates  VII,  VIII) 
(Diaporthe  hatatatis) 

This  rot  begins  at  one  end  and  slowly  works  toward 
the  middle  of  the  potato  or  to  the  other  end.  This 
results  in  a  firm  hard  brown  rot  which  causes  the  potato 
to  look  dry  and  mummified.  Small  dome-like  bumps 
are  just  noticeable  to  the  naked  eye ;  if  the  outer  surface 
of  the  skin  is  scratched  away,  the  tissues  beneath  present 
a  coal  black  appearance.  In  the  small  protuberances 
on  the  surface  are  to  be  found  millions  of  colorless 
spores,  which  serve  to  reproduce  the  fungus. 

While  dry-rot  attacks  the  stems  of  the  plants  in  the 
field  and  draw-bed  as  well  as  in  the  storage-house,  yet 
it  is  by  no  means  the  most  serious  of  the  rots.  It  is 
widely  distributed  throughout  the  country,  and  usually 
does  some  damage  wherever  found. 

JAVA  BLACK-ROT  (Plate  VII) 

(Diplodia  iubericola) 

This  rot  receives  its  name  from  its  first  discovery  in 
this  country  on  a  shipment  of  sweet  potatoes  imported 
from  Java.  The  disease  is  widely  distributed,  but  is 
most  common  in  the  South.  Potatoes  attacked  by  this 
disease  become  dry,  hard,  brittle,  coal  black  inside,  and 
hard  to  break.  Java  black-rot  usually  begins  at  one  end 
and  develops  very  slowly,  requiring  several  weeks  com- 
pletely to  destroy  a  tuber.  The  surface  of  the  potato  is 
very  rough,  the  skin  becoming  wrinkled  and  knots  or 
protuberances  abundant  over  it. 


Diseases  of  the  Sweet  Potato  167 

CHARCOAL-KOT 

(Sclerotium.  bataticola) 

A  rot  of  less  economic  importance  is  occasionally 
found  in  the  storage-houses  throughout  the  country, 
which  likewise  produces  a  black  decay.  This  form  of 
rot  differs  from  others  of  a  similar  appearance  by  the 
production  by  the  fungus  of  minute  spherical  resting 
bodies  throughout  the  potato,  rarely  on  the  surface. 
These  bodies  are  coal  black  and  stand  mostly  separated 
from  each  other.  If  the  surface  of  the  potato  is  care- 
fully opened,  these  bodies  can  be  seen  by  the  naked  eye 
buried  in  the  tissue.  Some  shrinking  and  drying  of  the 
potato  follow  an  infection  by  this  fungus.  The  total 
loss  to  the  crop  that  might  be  attributed  to  this  disease 
is  comparatively  small. 

CONTROL    OF    STORAGE    ROTS 

In  1918  the  writer  treated  a  quantity  of  stored  sweet 
potatoes  at  Ocean  Springs,  Mississippi,  in  the  following 
way:  The  decaying  potatoes  were  culled  out  and  the 
surfaces  of  the  remaining  good  ones  were  sprayed  with 
a  4-4-50  solution  of  bordeaux  mixture.  The  results 
were  very  gratifying.  Of  course  it  is  necessary  to 
have  plenty  of  air  in  the  store-house  until  the  surplus 
water  on  the  surface  is  dried  off.  However,  in  most 
cases  it  is  best  to  adhere  to  the  following  instructions 
taken  from  a  United  States  bulletin : 

"  The  United  States  could  and  would  produce  many 
more  sweet  potatoes  if  they  could  be  marketed  at  a  fair 
profit.  One  of  the  chief  barriers  to  the  extension  of 
the  industry  is  the  inability  of  the  farmers  to  keep  the 
potatoes  in  storage  so  that  they  can  be  placed  on  the 


168  The  Sweet  Potato 

market  in  the  winter,  when  prices  are  good.  As  a  result 
most  of  the  potatoes  in  the  South  are  consumed  locally 
and  placed  on  the  market  at  digging  time,  when  prices 
are  low.  Consequently,  few  sweet  potatoes  go  on  the 
northern  markets  in  the  winter,  and  even  in  the  South 
where  they  are  gTown  they  can  not  be  obtained  with  any 
degree  of  certainty  at  that  season  of  the  year.  It  is 
believed  that  if  storage  methods  and  principles  were 
better  understood,  more  potatoes  would  be  available  for 
winter  use  and  disposed  of  at  good  prices. 

"  The  success  of  the  industry,  however,  does  not  de- 
pend on  successful  storage  methods  alone.  It  is  a  well- 
known  fact  that  there  are  several  field  diseases  of  the 
sweet  potato,  the  best  known  of  which  are  black-rot, 
stem-rot  and  foot-rot.  The  storage  of  black-rot  potatoes 
must  necessarily  result  in  heavy  loss,  since  the  disease 
spreads  rapidly  throughout  the  bins.  Stem-rot  on  the 
other  hand,  does  not  produce  any  marked  decay  in  stor- 
age, but  it  may  open  the  way  for  storage-rot  organisms 
to  enter  the  potato.  It  therefore  becomes  imperative 
that  the  elimination  of  the  field  diseases  must  be  coupled 
with  a  well-regulated  system  of  storage. 

"  Great  care  should  be  exercised  in  handling  sweet 
potatoes  not  to  bruise  them  any  more  than  necessary. 
The  bruises  made  by  rough  handling  open  the  way  for 
storage-rot  organisms  to  enter.  A  farmer  would  never 
think  of  handling  apples,  oranges,  or  any  of  the  fruits 
in  the  way  that  sweet  potatoes  are  handled,  and  yet  a 
barrel  of  good  sweet  potatoes  will  bring  as  much  on  the 
market,  and  often  more  than  a  barrel  of  good  apples, 
and  sweet  potatoes  bruise  even  more  readily  than  apples. 
It  is  likely  that  if  sweet  potatoes  were  handled  with  the 
same  care   and  intelligence   as   apples,   little  difficulty 


Diseases  of  the  Sweet  Potato  1G9 

would    be    experienced    in    keeping    them    in    storage. 

"  After  the  potatoes  are  well  dried  in  the  field  they 
should  be  carefully  laid  in  an  open  crate  holding  about 
a  bushel  and  hauled  to  the  storage  house.  They  should 
not  be  poured  out  of  this  crate  into  a  bin,  but  stored  in 
the  crate  itself.  The  use  of  crates  permits  the  free  cir- 
culation of  air  among  the  potatoes,  a  condition  which 
can  not  be  obtained  if  they  are  piled  in  a  bin.  The 
crate  has  an  added  advantage  in  that,  as  many  potatoes 
can  be  taken  out  for  the  market  during  the  winter  as 
are  desired  without  disturbing  the  remainder.  Sweet 
potatoes  will  not  stand  frequent  handling,  and  for  that 
reason  it  is  unwise  to  disturb  a  pile  or  bin  unless  they 
are  all  marketed  at  the  same  time.  The  use  of  crates 
would  eliminate  this  danger. 

"  Potatoes  intended  for  storage  should  be  dug  as  late 
in  the  fall  as  is  consistent  with  weather  conditions. 
This  is  usually  just  preceding  frost.  Frozen  potatoes 
will  not  keep  well,  and  it  is  likely  that  a  heavy  frost 
will  injure  them  to  some  extent.  It  is  advisable,  too^ 
after  a  heavy  frost  to  cut  the  vines  at  once  and  dig. 
It  is  believed  that  warm,  dry,  sunny  weather  preceding 
a  frost  is  better  than  a  period  a  little  later  in  the  season 
following  a  frost.  To  wait  too  long  may  mean  that  in 
order  to  avoid  freezes  the  potatoes  must  be  dug  during 
bad  weather.  After  digging,  the  potatoes  should  be 
allowed  to  dry  as  long  in  the  sun  as  is  consistent  with 
Weather  conditions.  On  a  very  hot  day,  however,  it 
would  be  desirable  to  hurry  the  potatoes  to  the  shade 
after  their  surfaces  have  been  dried  in  the  sun." 


CHAPTER  IX 

INSECTICIDES,  FUNGICIDES  AND  SPRAY 
MACHINERY 

The  successful  grower  of  sweet  potatoes  will  be 
called  on  to  administer  preventatives  and  remedies 
for  insect  depredations  and  attacks  of  plant  diseases. 
It  is,  therefore,  necessary  that  he  should  be  familiar 
with  different  chemicals  used  as  poisons  for  insects  and 
as  remedies  for  plant  diseases,  and  he  should  in  addition 
have  a  general  knowledge  of  the  kinds  of  spray  machin- 
ery and  pumps  with  which  to  apply  them. 

Of  course,  there  are  many  areas  in  many  localities 
where  remedies  will  not  often  be  needed,  but  at  certain 
times  the  grower  will  probably  have  to  resort  to  spraying 
in  order  to  control  these  pests  and  diseases.  It  is, 
therefore,  thought  necessary  to  give  some  information 
concerning  the  more  important  sprays,  and  the  differ- 
ent forms  of  sprayers. 

INSECTICIDES  AND  FUNGICIDES 

Arsenate  of  lead  is  one  of  the  commonest  insecticides 
and  the  spray  may  be  made  as  follows : 

3  to  5  pounds  of  arsenate  of  lead. 
1  pound  of  fish-oil  soap. 
50  gallons  of  water. 

This  makes  an  average  solution  that  is  commonly  used 
170 


Insecticides,  Fungicides  and  Spray  Macliinery       171 

by  most  planters.  The  arsenate  of  lead  and  fish-oil 
soap  should  be  dissolved  in  2  or  3  gallons  of  water 
and  this  amount  poured  into  the  remainder  of  the  50 
gallons  and  thoroughly  stirred  until  the  mixture  is 
evenly  dissolved.  The  fish-oil  soap  is  added  only  as  a 
sticker  but  it  also  gives  a  more  even  covering  of  the 
plants.  However,  this  may  be  eliminated  with  all  the 
sprays  for  all  plants  except  those  that  have  slick  leaves. 
If  pow^dered  arsenate  of  lead  is  used,  one-half  the  above 
amount  should  be  mixed. 

Paris  green  is  a  chemical  compound  of  white  arsenic, 
copper  oxide  and  acetic  acid.  The  compound  is  known 
as  aceto-arsenite  of  copper.  When  properly  prepared, 
it  should  be  of  uniform  composition  and  contain  very 
little  insoluble  matter.  This  is  a  deadly  poison  and  is 
very  effective  when  used  for  biting  insects.  This  should 
be  prepared  by  dissolving  5  ounces  of  paris  green  and 
50  gallons  of  water,  and  if  desirable  the  fish-oil  soap, 
as  in  the  arsenate  of  lead  preparation,  may  be  used  or 
left  out,  as  it  is  only  necessary  for  sticking.  The 
grower  must  bear  in  mind  that  paris  green  will  burn 
the  plant  much  more  readily  than  arsenate  of  lead. 
To  prevent  this  burning,  it  is  advisable  that  a  small 
amount  of  hydratcd  lime-,  at  least  2  pounds,  be  used 
in  the  spray.  Paris  green  usually  costs  more  than 
arsenate  of  lead  and,  considering  its  burning  qualities, 
it  is  advisable  to  use  the  latter. 

Arsenite  of  lime  is  easily  prepared  at  home  and  is 
very  effective.     The  proportions  are: 

White  arsenic,  1  pound. 
Crystal  sal  soda,  4  pounds. 
Water,  1  gallon. 


172  The  Sweet  Potato 

These  ingredients  should  be  placed  in  an  iron  vessel, 
and  boiled  for  fifteen  or  twenty  minutes  or  until 
thoroughly  dissolved.  Forty  gallons  of  water  should 
be  added  to  1  quart  of  this  stock  solution,  and  3  pounds 
of  freshly  slacked  lime.  This  solution  is  cheaper  than 
the  other  arsenicals,  and  if  properly  prepared  and  ap- 
plied is  very  satisfactory. 

Tobacco  decoction  is  prepared  by  boiling  tobacco 
stems  and  other  refuse  of  tobacco,  1  pound  to  1  or  2 
gallons  of  water.  If  any  of  the  water  evaporates  while 
boiling,  enough  should  be  added  to  replace  it.  This  so- 
lution is  used  for  plant-lice  and  other  delicate  insects. 

Blach-leaf-40  or  nicotine  stdfate  may  be  purchased 
from  any  reliable  drug  dealer,  and  it  should  be  pre- 
pared by  adding  nicotine  sulfate  to  water  at  the  rate  of 
1  part  to  1000.  If  a  sticker  is  desired,  fish-oil  soap 
should  be  used  as  directed  in  other  sprays.  This  spray 
is  for  plant-lice  and  other  sucking  insects. 

Gold  dust  or  laundry  soap. —  A  good  insecticide  may 
be  prepared  by  mixing  4  pounds  of  gold  dust  or  com- 
mon laundry  soap  to  50  gallons  of  water.  When  the 
soap  is  used,  it  should  be  shaved  into  fine  slices  and 
boiled  in  1  or  2  gallons  of  water  until  thoroughly  dis- 
solved. This  stock  solution  should  then  be  poured  into 
the  proper  amount  of  water  and  stirred  or  churned 
until  it  is  dissolved. 

Poison  bran  mash  is  prepared  as  follows: 

1  pound  paris  green. 
25  pounds  wheat  bran. 
1/2  gallon  cheap  molasses. 
1/^  dozen  lemons  or  oranges. 
The  paris  green  and  bran  should  be  mixed  thoroughly. 


Insecticides,  Fungicides  and  Spray  Machinery       173 

and  the  molasses  mixed  with  1  gallon  water.  The 
lemons  or  oranges  should  be  chopped  into  very  fine  par- 
ticles and  put  in  the  sirup  and  the  poisoned  bran 
moistened  with  the  sirup  until  it  makes  a  stiff  mash. 
It  should  be  applied  very  late  in  evening  by  putting  one 
spoonful  near  each  plant  or  by  broadcasting  over  field. 
It  is  strongly  recommended  for  cut-worms  and  army- 
worms. 

Bordeaux  mixture  is  used  in  combatting  most  fungous 
diseases  and  also  repels  certain  insects,  such  as  flea- 
beetles.     It  is  prepared  as  follows : 

Unslacked  lime 4  pounds. 

Copper  sulfate  (bluestone) 4  pounds. 

Water    50  gallons. 

The  lime  should  bo  slacked  in  enough  water  to  make  a 
milk  of  lime  solution,  and  the  bluestone  should  be  dis- 
solved in  water  to  take  the  amount  in  the  formula. 
The  bluestone  solution  should  then  be  poured  into  the 
lime  and  this  mixture  diluted  to  the  full  50  gallons 
strength.  It  is  important  that  very  cold  water  be  used 
in  preparing  this  spray,  if  possible  ice  water.  The 
mixture  should  be  kept  in  a  very  cool  place.  Bordeaux 
mixture  may  be  combined  with  any  of  the  insecticides, 
thus  making  a  dual  spray. 

Carbon  hisulfid  is  a  fumigant  and  should  not  be  ap- 
plied to  live  plants  of  any  kind.  It  is  valuable  as 
a  storage  product  insecticide.  It  is  bought  from  drug- 
gists in  small  tin  packages  or  demijohns.  It  is  a  liquid 
and  is  applied  by  using  3  to  4  pounds  of  the  material 
to  1000  cubic  feet  space  for  a  period  of  30  hours.  It 
should  always  be  placed  in  an  open  vessel  on  top  of  the 
material  to  be  fumigated.     To  be  effective,  it  must  be 


174  The  Sweet  Potato 

applied  in  a  room  or  bin  that  is  practically  air-tight. 
Fire  must  be  kept  away  as  this  is  very  inflammable. 

SPKAY    MACHINERY 

Sprays  are  best  applied  by  the  use  of  proper  instru- 
ments, a  few  of  which  will  be  discussed  here.  For  the 
grower  that  has  only  a  few  rows,  a  small  hand  sprayer 
or  atomizer  may  be  used.  These  ordinarily  hold  about 
a  quart  and  may  be  bought  at  almost  any  hardware 
store.     These  are  usually  of  glass  or  tin. 

Knapsack  pumps  are  most  suitable  for  the  farmer  who 
has  a  small  patch,  from  one-half  to  several  acres. 
These  are  usually  made  of  galvanized  iron  or  copper  and 
are  strapped  on  the  back  so  that  the  operator  pumps 
with  one  hand  and  holds  the  nozzle  with  the  other.. 
They  ordinarily  hold  from  2  to  4  gallons.  The  pump 
should  have  a  good  agitator  or  mixer.  Bordeaux  mix- 
ture will  soon  eat  out  the  pump. 

Compressed  air  sprayers  are  small,  handy  and  very 
efiicient.  The  capacity  usually  runs  from  2  to  4  gallons, 
and  a  pressure  of  several  pounds  is  maintained  by  a 
small  air  pump  extending  down  into  the  tank.  The 
spray  is  released  by  turning  on  the  faucet  near  the  noz- 
zle. A  tank  of  spray  material  may  be  applied  with 
two  or  three  pumpings.  These  are  fitted  with  a  strap 
so  that  they  can  be  carried  over  the  shoulder  with  ease. 
The  top  should  be  screwed  on  and  not  clamped  on  over 
a  rubber  gasket. 

Barrel  pumps  are  the  most  serviceable  and  popular 
for  the  average  farm.  Much  more  work  can  be  accom- 
plished with  these,  and  very  efticiently.  These  barrels 
hold  from  50  to  60  gallons,  and  of  course  have  to  be 


Insecticides,  Fungicides  and  Spray  Machinery       175 

hauled  through  the  field  on  a  wagou,  cart  or  slide.  One 
man  is  needed  to  pump  and  keep  up  pressure,  while  an- 
other manages  the  nozzle.  In  buying  a  barrel  pump, 
the  following  suggestions  should  be  kept  in  mind:  (1) 
The  pump  should  be  guaranteed  to  furnish  80  to  100 
pounds  of  pressure  with  four  nozzles  running;  (2)  it 
should  have  a  large  air  chamber  within  the  barrel  and 
not  projecting  above  it;  (3)  as  many  working  parts  as 
possible  should  be  inside  the  barrel,  as  exposed  parts  are 
easily  broken;  (4)  the  cylinder,  plunger,  valves,  and 
all  working  parts  should  be  made  of  brass,  the  handle 
and  other  parts  of  malleable  or  galvanized  iron;  (5) 
there  should  be  a  good  mechanical  agitator  of  the  paddle 
type;  (6)  the  pump  should  be  so  attached  to  the  barrel 
that  it  may  be  quickly  removed  for  repairs;  (7)  valves 
and  their  seats  should  be  easily  removable  for  cleaning. 
Power  outfits. —  For  the  commercial  growers  who  pro- 
duce many  acres,  power  outfits  might  be  used.  How- 
ever, it  should  be  ascertained  first  that  the  barrel  type 
pump  will  not  do  the  work.  Power  sprayers  should  be 
mounted  on  substantial  trucks  with  wheels  that  may  be 
set  in  or  out  to  fit  different  width  rows.  These  outfits 
should  easily  run  six  to  eight  nozzles  so  that  several  rows 
may  be  sprayed  at  the  same  time.  All  the  working 
parts  of  the  machinery  should  be  easily  accessible  for 
repairs.  Often  the  most  simply  constructed  outfits  give 
the  best  satisfaction.  However,  a  cheap  pump  is  not 
satisfactory  and  one  should  buy  of  a  standard  company. 

Blisters. 

Often  dusting  will  answer  the  same  purposes  as  spray- 
ing and  the  work  can  be  done  much  faster.  For  the 
farmer  who  has  a  few  acres,  a  simple  duster  or  powder- 


176  The  Sweet  Potato 

gun  may  be  employed.  This  duster  has  tubes  which 
will  direct  the  dust  on  two  rows,  or  on  both  sides  of  one 
row,  and  regulates  the  amount  of  dust  used.  Large 
power  dusters  are  also  on  the  market,  but  the  average 
sweet  potato  grower  would  rarely  need  such  an  outfit. 

When  dusting  is  resorted  to,  it  must  be  remembered 
that  the  material  must  be  put  into  the  finest  form  of 
powder  possible.  This  is  necessary  in  order  that  the 
leaves  may  be  thoroughly  covered.  Coarser  dust  will 
not  stick  to  the  leaves  and  cover  them  as  evenly  as  the 
finer  kind,  neither  will  it  feed  through  the  machine  as 
satisfactorily.  The  chief  advantage  in  dusting  is  in  the 
time  saved. 

Nozzles,  hose,  ayid  fixtures. 

Three  types  of  nozzles  are  the  Bordeaux,  Vermorel, 
and  the  Disk.  For  applying  most  of  the  ordinary  in- 
secticides and  fungicides,  the  Vermorel  and  Disk  are 
preferable.     These  make  a  cone-shaped  spray. 

For  applying  bordeaux  mixture,  the  Bordeaux  type 
is  very  satisfactory.     This  makes  a  fan-shaped  spray. 

The  nozzle  that  can  be  easily  taken  apart  and  cleaned 
is  the  most  desirable. 

An  angle-form  nozzle  or  nozzles  with  elbow  joints 
should  be  used  in  order  that  the  spray  may  be  applied 
to  the  under  side  of  the  leaves.  A  good  quality  rubber 
or  fabric  hose  and  good  clamps  should  be  used  so  that  no 
leakage  will  occur.  Where  the  hose  bends  near  the 
pump  or  near  the  extension  rod,  it  should  be  wrapped 
or  supplemented  with  tape,  or  a  good  coil  of  wire  around 
it,  which  acts  as  a  supporter. 


CHAPTER  X 
HARVESTING  AND  STORAGE 

The  harvesting  and  transportation  of  sweet  potatoes 
to  local  and  northern  markets  begins  in  August  in  the 
extreme  southern  section  of  the  potato  area.  Along  the 
Gulf,  many  potatoes  are  put  on  the  market  in  the 
latter  part  of  July.  This  is  not  a  good  practice,  how- 
ever, and  is  only  due  to  the  fancy  prices  that  they  com- 
mand at  this  time.  The  yield,  as  a  rule,  is  light  at  this 
season,  as  the  potatoes  have  not  attained  their  growth, 
and  a  considerable  loss  in  weight  results.  The  main 
supply  of  the  crop  for  home  and  commercial  purposes 
is  han^ested  late  in  the  fall,  the  usual  time  being  about 
the  first  frost.  When  the  potatoes  are  thoroughly 
matured,  a  slight  yellowish  tinge  on  the  leaves  and  the 
absence  of  any  new  growth  is  noticeable.  Another 
means  which  many  growers  find  very  reliable  is  to 
break  a  tuber  in  two ;  if  ripe  the  broken  part  dries  after 
a  few  minutes'  exposure ;  if  still  green  and  in  a  grow- 
ing state,  the  broken  part  remains  milky  and  sticky. 

While  the  sweet  potato  vines  usually  are  very  luxu- 
riant, the  foliage  is  tender  and  easily  injured  by  frost. 
Light  frost,  however,  causes  very  little  injury,  but  a 
heavy  frost  or  a  light  freeze  may  result  in  considerable 
damage,  if  the  vines  are  not  cut  away  immediately. 
This  latter  practice  is  to  prevent  the  frost-injured  sap 
from  passing  down  to  the  tuber.  In  certain  seasons 
177 


178  The  Sweet  Potato 

when  potatoes  cannot  be  dug  at  the  first  frost  or  at  con- 
venience, it  is  advisable  to  rake  loose  dirt  over  the  rows 
and  thus  afford  them  protection  from  the  cold. 

The  greater  part,  of  the  farmers  who  raise  only  a  small 
patch  of  potatoes  for  home  consumption  use  various 
hand  and  horse-driven  implements  for  digging.  In 
fact,  many  tools  from  the  ordinary  hay-fork  to  the  one- 
horse  turning-plow  are  employed.  When  the  fork  is 
resorted  to,  the  work  will  be  easier  and  more  satisfac- 
tory if  a  broad,  flat,  short-handled  fork  is  used,  one 
with  eight  to  fourteen  tines  somewhat  similar  to  the  seed- 
fork. 

When  potatoes  are  dug  by  a  turning-plow,  it  will  be 
advisable  to  go  twice  through  each  row,  turning  the  soil 
to  both  sides.  By  removing  the  mold-board  and  putting 
in  several  rods,  either  of  wood  or  metal,  the  earth  will 
sift  through  and  leave  the  potatoes  on  the  surface.  In 
the  larger  fields  it  is  advisable  to  use  the  regular  potato- 
diggers  manufactured  for  the  purpose.  These  are  usu- 
ally the  two-  or  three-horse  plows;  they  have  extension 
rods  or  fingers ;  while  plowing  up  the  row  the  soil  sifts 
through  and  leaves  the  potatoes  on  top,  where  they  may 
be  easily  picked  up  and  put  in  the  basket.  In  either 
the  one-  or  two-horse  plow,  it  is  advisable  to  use  the 
rolling  cutting-colter,  which  cuts  the  vines  and  makes 
the  plowing  much  easier.  If  the  one-wing  plow  is  em- 
ployed, one  colter  is  sufficient ;  if  a  double-winged  plow, 
a  double  roller-colter  is  used  to  cut  the  vines  from 
both  sides  of  the  row  at  once. 

It  is  desirable  that  the  soil  should  be  comparatively 
dry  at  harvesting  time  in  order  that  the  potatoes  may 
be  drier  and  smoother  and  more  satisfactorily  handled- 
After^the  potatoes  are  plowed  out,  they  should  be  allowed 


Harvesting  and  Storage  179 

to  remain  in  the  field  until  the  surface  and  adhering 
soil  are  thoroughly  dry.  However,  they  should  not  he 
left  long  enough  to  sunburn  or  bake.  In  handling  in 
the  field,  all  the  soil  should  be  removed  from  the  tubers. 
It  is  not  advisable  that  they  be  left  exposed  to  cool  nights. 
Whether  the  potatoes  are  for  storage,  home  use  or 
shipping,  they  should  be  crated  in  the  field,  thus  elim- 
inating one  handling.  The  fewer  handlings  during 
harvest  or  storage,  the  less  likely  they  are  to  become 
bruised  and  rot.  If  for  storage,  suitable  baskets  or 
hampers  should  be  used ;  the  first  grade  potatoes  should 
be  packed  separately  from  the  seconds  or  culls.  If  for 
shipping  to  market,  either  barrels  or  hampers  should  be 
provided. 


One  of  the  greatest  limiting  factors  in  the  production 
of  sweet  potatoes  for  market  has,  until  the  present  time, 
been  the  lack  of  proper  storage  facilities.  In  the  fall 
at  digging  season  when  the  bulk  of  this  crop  is  offered 
for  sale,  the  market  is  usually  flooded  and  the  price  is 
correspondingly  low ;  while  during  the  spring  and  sum- 
mer months,  sweet  potatoes  are  high  in  price  and  hard 
to  obtain  at  any  figure. 

With  the  advent  of  the  scientific  storage-house,  the 
fear  of  loss  from  rot  is  no  longer  justified  and  the  fact 
that  there  is  an  all-year  demand  for  sweets  should  be  a 
great  incentive  to  producers  who  avail  themselves  of 
efficient  storage.  In  an  effort  to  remedy  this  poor  dis- 
tribution and  eliminate  the  unnecessary  waste  from 
decay  by  stimulating  the  erection  of  proper  storage- 
houses  and  the  correct  manipulation  of  them,  consider- 
able work  has  recently  been  done  by  the  United  States 


180  The  Sweet  Potato 

Department  of  Agriculture  and  also  individual  growers. 
This  attention  has  been  rewarded  by  the  development  of 
a  very  economical  and  efficient  plan  of  storage  which  is 
in  the  reach  of  all  growers.  The  future  commercial 
development  of  the  industry  will  no  doubt  be  constructed 
on  the  basis  of  storage  possibilities. 

Essentials  in  keeping  sweet  potatoes. 

To  keep  sweet  potatoes  successfully  in  storage  so  that 
they  will  not  only  be  protected  from  decay  while  in  the 
curing-house  but  will  hold  up  well  after  being  removed 
whether  for  shipping,  seed  purposes,  or  other  uses, 
some  essential  principles  must  be  carefully  observed. 
In  the  first  place,  every  precaution  should  be  taken  to 
prevent  the  spread  of  diseases,  several  of  which  seriously 
affect  the  sweet  potato  crop  in  storage.  The  time  of 
digging  and  housing  has  been  found  to  have  a  very 
marked  influence  over  the  keeping  qualities  of  this 
crop.  Extreme  care  in  handling  is  absolutely  essential 
if  the  potatoes  are  to  be  stored  without  bruises,  which 
greatly  interfere  with  their  keeping  qualities  by  facili- 
tating the  spread  of  numerous  fungous  diseases  in  the 
storage-house  through  breaks  in  the  skins.  It  has  been 
found  that  sweet  potatoes  should  be  well  dried  with 
warm  dry  air  during  the  curing  process  and  afterwards 
kept  at  a  temperature  ranging  from  40°  to  60°  through- 
out the  entire  storage  period.  In  keeping  potatoes  suc- 
cessfully, whether  in  a  bank,  storage-house  or  othenvise, 
it  is  essential  that  both  proper  insulation  and  ventilation 
be  provided. 

Care  in  hotbed  for  disease. —  The  successful  curing 
and  storage  of  sweet  potatoes  begins  in  the  plant-bed. 
Too  often  little  attention  is  paid  to  the  kind  of  bedding 


Harvesting  and  Storage  181 

stock,  and  frequently  sweet  potatoes  are  used  for  seed 
purposes  which  are  diseased  when  they  are  bedded. 
Such  potatoes  are  sure  to  produce  diseased  pUmts,  which 
in  turn  carry  the  disease  to  the  field  and  often  trans- 
mit them  to  the  tubers.     Black-rot  is  the  commonest  dis- 


FiGtJRE  24. —  Outdoor  storage  pits  commonly  used  for  keeping 
small  quantities  of  sweet  potatoes.  Note  proximity  of  pits  to 
hotbeds,  a  bad  location  from  the  disease  standpoint. 

ease  affecting  the  sweet  potato  conveyed  in  this  manner. 
Such  diseased  potatoes  will  be  difficult  to  keep  under  any 
conditions.      (See  Fig.  24.) 

Yine  and  draw  jJotatoes. —  A  very  important  means 
of  controlling  sweet  potato  diseases  and  preventing  their 
spread  is  by  the  use  of  vines  as  a  means  of  propaga- 
tion. The  general  plan  now  followed  by  most  success- 
ful growers  is  to  plant  a  small  seed  patch  with  draws 
or  plants,  and  from  this  first  planting  cut  vines  to  set 
out  the  remaining  acreage.  In  this  way,  no  disease 
which  might  have  been  present  in  the  plant-bed  is  car- 
ried to  the  field.  Potatoes  propagated  by  means  of 
vines  seem  to  keep  better,  generally  speaking,  than  those 


182  The  Sweet  Potato 

produced  from,  draws  or  plants.  This  may  be  ex- 
plained in  several  ways.  In  the  first  place,  sweet 
potatoes  produced  from  draws  are  likely  to  be  planted 
early  and  are  often  left  in  the  ground  until  they  are  over- 
mature. When  this  condition  exists,  the  late  fall  rains 
so  prevalent  in  sweet  potato  growing  sections  are  liable 
to  injure  the  quality  and  consequently  ease  of  keeping 
of  these  potatoes,  which  have  already  reached  their  max- 
imum growth.  Another  reason  for  the  apparent  diffi- 
culty in  keeping  sweet  potatoes  grown  from  plants  is 
that  there  is  a  greater  tendency  to  produce  large 
cracked-open  jumbos,  or  as  they  are  sometimes  called 
''  mother  potatoes."  In  handling,  these  potatoes  are 
more  likely  to  become  bruised  and  consequently  will  be 
more  difficult  to  keep  in  good  storage  condition.  Many 
growers  very  strongly  recommend  tubers  grown  from 
vines  as  being  the  best  keepers. 

Harvesting. —  To  secure  the  maximum  yield  and  de- 
velop the  highest  quality  in  sweet  potatoes,  they  should 
be  allowed  to  mature  before  being  harvested.  Sweet 
potatoes  which  are  planted  early  should  not  be  left  in 
the  ground  long  after  they  are  mature,  since  there  is  a 
tendency  to  produce  ill-shaped  jumbos  which  will  have 
to  be  marketed  at  a  disadvantage.  Potatoes  planted  in 
midseason  are  ordinarily  not  mature  until  about  the 
time  of  the  first  frost  and  the  common  practice  is  to  let 
them  remain  in  the  field  until  this  time.  After  frost 
has  fallen,  harvesting  should  be  done  immediately  or 
if  necessary  to  postpone  it  for  a  few  days  the  vines 
should  be  cut  off  at  once.  It  is  well  to  get  the  potatoes 
out  as  soon  as  possible  after  the  vines  have  been  cut. 

Care  in  handling. —  One  of  the  most  important  con- 
siderations to  be  kept  in  mind  constantly  if  sweet  pota- 


Harvesting  and  Storage  183 

toes  are  to  be  stored  successfully  is  the  method  of  hand- 
ling. More  potatoes  are  lost  to  the  grower  through  care- 
less handling  and  consequent  bruises  than  perhaps  any- 
other  one  cause.  No  definite  method  of  handling  can 
be  outlined,  as  individual  cases  necessarily  require  dif- 
ferent methods,  but  Avhatever  system  of  handling  is 
used,  sweet  potatoes  should  never  be  thrown  into  heaps 
in  the  field,  hauled  loosely  in  a  wagon  body,  or  handled 
in  sacks.  A  sack  is  the  poorest  container  for  handling 
potatoes,  either  in  shipping  or  in  storage.  A  large 
part  of  the  potatoes  handled  in  any  of  the  above  men- 
tioned ways  are  sure  to  become  bruised  and  the  skins 
broken,  which  permit  an  easy  entrance  of  diseases  of  all 
kinds.  Sweet  potatoes  should  be  handled  as  little  as 
possible,  graded  in  the  field,  and  carefully  placed  in 
boxes  or  baskets  (preferably  small  bushel  crates  in 
which  they  will  be  stored).  They  should  be  hauled  to 
storage  in  the  same  containers  and  thus  bruises  and 
consequent  loss  will  be  reduced  to  a  minimum.  Many 
yam  varieties  are  more  susceptible  to  bruising  than 
such  hardy  kinds  as  the  White  Triumph  and  the  Hay- 
man. 

Curing  and  storing. —  Whether  sweet  potatoes  are 
stored  in  a  bank  or  a  house,  they  should  be  given  proper 
insulation  and  thorough  ventilation.  Insulation  pro- 
vides conditions  which  will  prevent  freezing.  In  a 
bank,  insulation  is  provided  by  heaping  earth  several 
inches  deep  over  the  potatoes;  in  a  storage-house  by  a 
dead  air  space  in  a  double  wall.  In  a  bank,  ventilation 
is  se<iured  by  a  ventilator  in  the  top  and  sometimes 
others.  When  sweet  potatoes  are  first  harvested  they 
contain  excess  moisture  which  is  given  off;  if  this  excess 
moisture  is  not  carried  out  of  the  storage-room  by  a 


184 


The  Sweet  Potato 


thorough  circulation  of  air,  it  will  collect  on  the  outside 
of  the  potatoes  and  on  the  walls  of  the  room,  thus  caus- 
ing a  humid  condition  and  favoring  the  spread  of 
storage  diseases.  This  condition  is  especially  suited 
to  the  gro\vth  and  spread  of  ordinary  bread  mold,  which 
is  present  everywhere  and  which  destroys  a  larger  part 
of  the  sweet  potato  crop  in  the  form  of  soft-rot  or  ring- 
rot.     To  prevent  the  condition  just  outlined,  it  is  abso- 


Figure  25. —  A  pile  of  sweet  potatoes  to  be  covered  with  cane 
tops  and  soil.  Note  the  absence  of  ventilating  hole  which  should 
extend  through  the  center  of  the  pile. 

lutely  essential  that  thorough  ventilation  be  secured 
which  will  carry  the  surplus  moisture  out  of  the  storage- 
room,  whether  it  be  a  bank  or  a  house.  It  has  been 
found  that  the  proper  ventilation  and  the  desired  tem- 
perature can  be  more  easily,  economically,  and  surely 
secured,  by  using  a  properly  constructed  and  operated 
storage-house  than  by  the  use  of  a  potato  bank.  (See 
Fig.  25.) 


Harvesting  and  Storage  185 

Advantages  of  the  storage-house  over  the  hank. 

The  storage-house  has  a  great  advantage  over  the 
bank  in  that  the  two  main  essentials  in  keeping  sweet 
potatoes  (proper  temperature  and  ventilation)  can  he 
regulated.  In  a  storage-house  this  is  done  by  means  of 
artificial  heat  and  specially  constructed  flues,  ventilators 
and  windows,  whereas  in  a  bank,  ventilation  must  be 
depended  on  entirely,  by  means  of  an  apparatus  which 
cannot  be  controlled  conveniently.  Often  sweet  pota- 
toes may  be  kept  very  successfully  in  a  bank,  especially 
in  a  dry  year  when  potatoes  do  not  contain  an  unusually 
large  amount  of  surplus  sap,  or  if  very  careful  attention 
is  given  to  the  control  of  ventilators  in  the  bank  when 
conditions  are  ideal.  In  some  years  nearly  all  sweet 
potatoes  are  lost  by  soft-rot,  which  spreads  very  rapidly. 

A  maintenance  of  the  proper  temperature  during  the 
storage  period,  after  the  potatoes  have  been  cured,  is 
very  important.  Such  a  temperature  can  easily  be 
maintained  in  a  properly  constructed  storage-house, 
while  it  is  very  difficult  to  accomplish  with  the  bank 
method,  especially  in  freezing  weather  when  the  cold 
is  likely  to  penetrate  the  bank,  thus  chill  the  potatoes 
and  cause  them  to  decay. 

Even  though  the  bank  method  were  satisfactory  in 
other  respects,  the  extra  cost  of  building  these  banks 
each  year  and  the  expense  involved  in  moving  the  pota- 
toes from  such  storage,  especially  in  bad  weather,  makes 
them  very  uneconomical.  To  show  the  economy  of  a 
permanent  house  over  temporary  banks,*  even  when  the 
loss  from  rot  in  the  house  is  as  much  as  that  in  a  bank, 
the  following  record  is  given  of  a  house  actually  oper- 
ated in  south  Mississippi  during  1918.     It  should  not 


186  The  Sweet  Potato 

be  concluded  from  these  figures  that  a  loss  of  30  per  cent 
from  rot  is  representative  of  the  efficiency  of  a  properly 
operated  storage-house ;  in  reality,  well-constructed  and 
operated  houses  will  keep  sweet  potatoes  with  practically 
no  loss  from  rot.  The  figures  on  this  inefficient  house 
are  given  to  emphasize  the  economy  even  under  adverse 
conditions. 

On  December  15,  1259  bushels  of  sweet  potatoes  were 
stored  in  a  2000-bushel  house.     The  cost  of  storage  was : 

$62.95     Estimated    cost    of    handling   1259    bushels    at    5 

cents  a  bushel. 
48.00     Interest  on  $600.00,  value  of  the  house,  at  8  per 

cent  for  one  year. 
30.00    Annual   depreciation   in   value   of  house   costing 

$600.00. 
12.00     Cost  of  three  cords  wood  used  in  curing  potatoes. 
282.75     Loss  from  rot  and  shrinkage.     30  per  cent  of  1259 

bushels  valued  at  75  cents  a  bushel  at  time  of 

storing. 
12.50     Interest  on  investment  of  1259  bushels  of  potatoes 

valued  at  75  cents  a  bushel. 


$448.20     Total  cost  of  storing  1259  bushels  potatoes. 
944.25     Value  of  1259  bushels  potatoes  at  time  of  storing 
at  75  cents  a  bushel. 


$1,392.45     Total  cost  of  potatoes  stored. 


537  bushels  sold  at  $2.00  net $1,074.00 

125  bushels  seed  potatoes  on  hand  valued  at  $2.00  250.00 

80  bushels  culls  on  hand  valued  at  70  cents 56.00 

100  bushels  fed  to  stock  valued  at  70  cents 70.00 

20  bushels  sold  on  local  market  at  $1.00 20.00 

20  bushels  used  at  home  valued  at  $1.00 20.00 

377  bushels  lost  by  rot  and  shrinkage 


Harvesting  and  Storage  187 

1,259  bushels  total  —  Brought  when  sold $1,490.00 

Total  cost  of  1259  bushels...   1,392.45 


Profit  by  storing $97.55 

Estimating  the  cost  of  putting  this  same  1259  bushels 
of  potatoes  up  in  banks,  the  following  figures  are  given 
on  fifty  banks  holding  25  bushels  each,  with  the  excep- 
tion of  one  which  would  contain  34  bushels : 

$62.95     Estimated    cost    of   handling    1259    bushels    at    5 
cents  a  bushel. 

282.75     Loss  from  rot  and  shrinkage.     30  per  cent  of  1259 
bushels  at  75  cents  a  bushel  at  time  of  storing. 
12.50     Interest  on  investment  of  1259  bushels  valued  at 
75  cents  a  bushel  at  time  of  storing. 

222.50  Estimated  cost  of  putting  up  fifty  banks  of  pota- 
toes —  forty-nine  banks  containing  25  bushels 
and  one  bank  containing  34  bushels  —  $4.45  a 
bank. 
5.93  Interest  on  money  invested  in  bank  material, 
$222.50,  at  8  per  cent  for  four  months,  the  aver- 
age banking  period. 


^586.63     Total  estimated  cost  of  storing  1259  bushels  of 

potatoes  in  banks. 
944.25     Value  of  these  potatoes  at  75  cents  a  bushel. 


$1,530.88     Total  cost  of  potatoes  if  they  were  stored  in  banks. 
1,490.00     Actual  selling  price  of  the  potatoes. 


$40.88     Money  lost  by  storing  potatoes  in  banks,  if  they 
were  just  as  efficient  as  houses. 

Five  cents  a  bushel  was  estimated  as  being  the  cost 
of  removing  the  potatoes  from  the  storage-house.  It  is 
computed  that  the  cost  of  putting  potatoes  in  the  house 
would  be  approximately  the  same  as  loading  them  on 
car  to  ship  when  dry,  thus  offsetting  expense  of  filling 


188  The  Sweet  Potato 

the  house.  In  this  connection  it  will  be  noted  that  377 
bushels  is  the  estimated  loss  of  30  per  cent  from  shrink- 
age and  rot,  and  yet  the  cost  of  removing-  potatoes  was 
figured  at  5  cents  a  bushel  on  the  full  1259  bushels  orig- 
inally stored.  This  is  thought  fair  because  of  the  extra 
trouble  involved  in  removing  and  disposing  of  the  rotten 
stock. 

In  comparing  storage  methods,  no  difference  was 
made  in  the  cost  for  removing  from  bank  and  from 
storage-house.  However,  it  is  universally  agreed  by 
those  who  have  used  the  house  that  this  expense  is  con- 
siderably less  than  with  the  bank. 

Attention  is  called  to  the  fact  that  interest  on  house 
investment  was  charged  for  full  twelve  months,  while  on 
the  bank  only  for  the  period  of  storage.  In  making  this 
comparison,  it  must  be  remembered  that  the  potato  house 
makes  an  excellent  store-room  for  articles  other  than 
potatoes  during  the  other  six  or  eight  months  of  the  year. 

In  computing  depreciation,  the  value  of  the  house 
was  considered  as  remaining  constant,  while  in  reality  if 
the  house  depreciated  5  per  cent  annually,  this  value 
would  be  $30.00  less  the  second  year,  the  third  year 
$28.50  less  than  the  second,  and  so  on,  thus  making  the 
depreciation  in  actual  money  value  less  each  year.  The 
banks  were  considered  as  having  to  be  made  new  each 
season,  and  were  estimated  at  costing  $4.45  each,  using 
low-grade  lumber  at  $30.00  per  M  (not  including  a 
board  shelter  for  them)  and  calculating  labor  involved 
in  building  and  hauling  pine  straw. 

It  will  be  noticed  that  the  loss  from  shrinkage  and 
rot  is  calculated  on  the  basis  of  being  equal.  The  actual 
shrinkage  in  a  bank  would  be  a  little  less  but  the  loss 
from  rot  under  the  same  condition  would  unquestionably 


Pl\te  VII.— Sweet  potato  diseases,  a,  Sweet  potato  show- 
injr  the  characteristic  shriveling  produced  by  the  root-rot  fun- 
<Tus  h  A  sweet  potato  showing  discoloration  caused  by  the 
scurf  fungus,  c  and  d,  Showing  ring-rot,  frequently  found  in 
storage-houses,  e,  Java  black-rot.  A  sweet  potato  showing 
the  d?v  mummied  condition  produced  by  the  fungus.  Note  the 
numerous  pimple-like  protuberances  containing  spores  borne  on 
the  surface.  /,  Foot-rot.  g,  Dry-rot.  h,  Black-rot.  A  sweet 
potato  showing  the  black  circular  spot  caused  by  black-rot 
fungus. 


Harvesting  and  Storage  189 

have  been  considerably  greater.^  The  loss  froifi  rot 
would  have  been  much  reduced  if  the  potatoes  had  been 
dug  and  stored  one  month  earlier. 

The  cost  of  all  operations  is  calculated  on  the  basis  of 
$4.00  a  day  for  team  and  wagon  and  $3.00  a  day  for 
man  labor. 

That  a  storage-house  built  by  government  specifica- 
tions and  operated  according  to  government  recom- 
mendations Avill  keep  sweet  potatoes  in  storage  in  much 
better  condition  and  do  it  more  economically  than  will 
a  bank,  has  been  demonstrated  on  a  number  of  farms  in 
the  past  year  throughout  the  entire  South. 

Construction  of  the  storage-liouse  (Figs.  26-30). 

Many  types  of  storage-houses  are  now  in  operation. 
The  first  storage  place  was  perhaps  a  cellar  under 
ground  in  which  potatoes  were  kept  during  the  winter. 
Next  came  a  potato  house  level  with  the  top  of  the 
ground,  using  the  soil  as  a  natural  floor,  filling  the 
hollow  walls  with  earth  or  other  filling  to  prevent  freez- 
ing .  In  this  house  a  stove  was  sometimes  installed  to 
facilitate  drying.  This  was  a  great  improvement  over 
either  the  pit,  cellar,  or  bank,  for  being  above  the  ground 
it  was  afforded  drainage  and  ventilation,  the  expense  of 
moving  potatoes  from  storage  was  lessened  and  the  use 
of  artificial  heat  was  gained.  Since  this  first  type  of 
house  was  built,  errors  have  been  corrected,  experiments 
have  been  conducted  and  improvements  made. 

The  best  type  of  house  for  the  individual  farmer  who 
wishes  to  store  from  500  to  5000  bushels  of  potatoes  is 

1  Ala.  Exp.  Sta.,  which  shows  a  loss  of  $8,946,000,  representing 
10  per  cent  loss  from  field  diseases  and  50  per  cent  from  rot  in 
storage  of  sweet  potatoes  in  1018. 


190  The  Sweet  I'otato 

the  flne  herein  illustrated  and  described  known  as  the 
government  sweet  potato  storage-house.  It  is  now  con- 
cluded by  some  experiment  stations  that  any  house  hav- 
ing a  capacity  above  5000  bushels  should  be  heated  by 
hot  water  or  some  other  system  which  will  give  an  even 
distribution  of  temperature  in  all  parts  of  the  house. 
Various  commercial  concerns  have  endeavored  to  make 
improvements  on  these  large  houses,  and  several  patented 
curing  processes  are  now  being  promoted  with  some 
success. 

A  sweet  potato  storage-house  should  be  located  on  a 
well-drained  spot.  If  a  commercial  house,  it  should  be 
near  the  railroad  and  as  convenient  to  the  field  as 
possible.  If  for  home  use,  it  could  be  conveniently 
situated  in  the  back  yard,  so  as  to  be  readily  accessible 
at  all  times. 

Details  of  the  construction  of  the  sweet  potato  stor- 
age-house are  reprinted  from  Farmers'  Bulletin  970: 

"  Sweet  potato  storage  houses  may  be  built  of  wood, 
brick,  hollow  tile,  cement,  or  stone.  Wooden  houses 
are  preferable,  because  they  are  cheaper  and  easier  to 
keep  dry  than  the  other  types.  It  is  difficult  to  keep 
moisture  from  collecting  on  the  walls  of  a  cement,  stone, 
or  brick  house.  Where  such  houses  are  built  for  sweet- 
potato  storage  they  should  be  lined  with  lumber,  so  as 
to  keep  the  air  in  the  house  from  coming  in  contact  with 
the  masonry  walls.  It  is  best  to  build  sweet-potato  stor- 
age houses  on  foundations  that  allow  a  circulation  of 
air  under  them-  The  "  dugout "  or  house  built  partly 
imder  the  ground,  is  not  satisfactory  for  storing  sweet 
potatoes  in  the  South,  because  it  is  practically  impossi- 
ble to  keep  this  type  of  house  dry,  and  moisture  in  the 
storage  house  will  cause  the  crop  to  rot. 


Tiarvesling  and  Storage 


191 


"  The  foundation  of  the  storage  house  may  be  in  the 
form  of  pilhirs  or  solid  walls  and  should  be  of  such  a 
height  that  the  floor  is  about  on  the  level  of  the  bottom 
of  the  wagon  bed,  while  the  footings  should  be  carried 
below  the  frost  line  or  to  solid  ground.  Girders  G  by 
10  or  8  by  8  inches  in  size  are  usually  placed  on  pillars. 

"Where  cement,  brick  or  stone  foundation  walls  are 
built,  they  should  extend  18  to  20  inches  above  the 
ground  level ;  and  plates  2  to  3  inches  thick  and  8  to  10 
inches  wide  should  be  placed  on  the  wall.  In  using 
walls  for  the  foundation  it  is  necessary  to  provide  means 
for  ventilation  under  the  house.  This  can  be  done  by 
placing  small  windows  in  the  foundation  every  10  to  12 
feet.  Even  where  solid  outside  foundation  walls  are 
used  it  is  advisable  to  use  pillars  for  the  center  supports. 

"  The  principles 
of  constructing  stor- 
age houses  of  vari- 
ous sizes  are  very 
much  the  same ; 
therefore,  only  one, 
the  12  by  16  foot 
house,  will  be  de- 
scribed (see  Fig. 
26). 

"  For  this  small 
storage  house,  hav- 
ing a  capacity  of 
400  to  500  bushels, 
build  three  rows  of 
pillars,  one  row  under  each  side  and  one  under  the  cen- 
ter of  the  house.  Girders  6  by  10  inches  in  size  are 
placed  on  the  pillars  and  on  these  2  by  8  inch  joists, 


Figure  26. —  Cross-section  of  a 
small  sweet  potato  storage-house 
(12x  IG  feet). 


192  The  Sweet  Potato 

spaced  12  inches  apart  from  center  to  center.  The  walls 
of  the  storage  house  are  made  by  setting  2  by  4  inch 
studs  on  the  girders  every  two  feet  and  nailing  them  to 
the  sleepers.  On  the  outside  of  the  studs  1  by  6  inch 
boards  are  nailed  diagonally  to  brace  the  wall;  over 
these  a  layer  of  heavy  building  paper  is  tacked  and 
matched  siding  then  put  on.  A  layer  of  1  by  6  inch 
boards  is  nailed  on  the  inside  of  the  studding,  then  a 
layer  of  building  paper,  and  over  this  matched  boards. 
In  the  lower  South,  the  first  layer  of  boards  on  the  inside 
of  the  studding  may  be  omitted  so  far  as  the  control  of 
temperature  is  concerned,  but  in  regions  of  high  humid- 
ity (near  the  seacoast)  it  is  deemed  advisable  to  use  four 
layers  of  boards,  two  on  the  inside  and  two  on  the  outside 
of  the  frame,  as  suggested  above.  The  tighter  the  walls, 
the  less  difficulty  will  be  encountered  in  controlling  both 
temperature  and  moisture.  Two  2  by  4  inch  pieces 
should  be  placed  on  top  of  the  studding  for  eave  plates, 
to  which  the  rafters  are  nailed.  The  floor  is  made  by 
laying  1  by  6  inch  sheathing  over  the  joists,  then  a 
layer  of  heavy  building  paper  and  over  this  1  by  4  inch 
tongue-and-groove  flooring.  The  building  may  be  cov- 
ered with  shingles,  roofing  paper,  galvanized  iron,  or 
any  other  kind  of  roofing  material ;  but  galvanized  iron 
is  to  be  preferred,  because  it  is  durable  and  lessens  dan- 
ger from  fire.  Use  2  by  4  inch  scantling  for  rafters  and 
make  the  roof  tight  to  keep  out  the  cold.  The  rafters 
should  be  cut  to  fit  over  the  plate  at  the  lower  end  and 
to  fit  snugly  against  the  ridgepole  at  the  upper  end. 
On  the  outside  of  the  rafters  put  a  layer  of  1  by  6  inch 
sheathing,  and  over  this  the  roofing  material.  On  the 
inside  of  the  rafters  aail  a  layer  of  1  by  G  inch  sheath- 
ing, then  a  layer  of  heavy  building  paper,  and  over  this 


Harvesting  and  Storage  193 

a  layer  of  tongiie-and-groove  coiling.  If  desired,  joists 
may  be  placed  across  the  building  on  top  of  the  eave 
plates,  and  the  sheathing,  paper,  and  tongue-and-groove 
material  nailed  to  the  under  side  of  them  instead  of  to 
the  rafters.  These  joists,  if  securely  nailed  to  the 
plate,  will  serve  for  tying  the  sides  of  the  building 
together,  as  well  as  for  carrying  the  insulated  ceiling. 
In  a  large  house  this  method  of  ceiling  is  very  satisfac- 
tory, as  it  gives  loft  space  above  the  storage  room  and 
requires  less  ceiling  material. 

"  The  sides  of  the  building  should  be  tied  together,  to 
prevent  spreading.  This  can  be  done  by  nailing  2  by 
4  inch  pieces  to  the  plates  or  to  the  lower  ends  of  the 
rafters.  It  would  be  an  advantage  to  have  these  pieces 
over  the  bin  supports. 

"  The  space  between  the  w\alls  should  be  left  open, 
because  any  material  used  to  keep  out  the  cold  will 
absorb  moisture.  ]\Iany  storage  houses  have  been  built 
with  sawdust,  shavings,  or  similar  material  between  the 
walls,  but  this  practice  should  never  be  followed.  Saw- 
dust will  take  up  moisture  and  when  once  wet  will  never 
dry  out.  This  moisture  will  keep  the  house  damp  and 
cause  the  walls  to  rot.  The  air  space  is  a  good  insulator 
if  the  walls  are  made  tight,  and  they  will  be  tight  if 
the  plans  given  are  followed. 

"  Thorough  ventilation  is  necessary  in  a  storage  house. 
This  is  provided  by  means  of  windows,  doors,  and  ventil- 
ators in  the  floor  and  through  the  roof.  The  openings 
in  the  floor  around  the  stove  prevent  overheating  the 
potatoes  near  the  stove.  The  bottom  of  the  windows 
should  be  within  8  inches  or  2  feet  of  the  floor. 
The  windows  and  doors  must  be  made  so  as  to  close 
tightly  to  keep  out  the  cold.     All  windows  should  be 


194  The  Sweet  Potato 

made  to  open  from  the  outside,  as  the  bins  will  in- 
terfere with  opening  them  from  the  inside.  Where 
glass  windows  are  used,  outside  shutters  are  put 
on,  and  these  should  be  well  padded.  Some  of  the 
windows  should  be  made  of  glass,  so  as  to  admit  light 
without  letting  in  cold  air,  as  it  is  necessary  to  have 
a  light  when  working  in  the  house  and  in  cold  weather 
the  house  should  not  be  kept  open.  All  of  the  open- 
ings must  be  made  so  that  they  can  be  closed  quickly 
and  tightly  whenever  necessary.  The  ventilators  in 
the  roof  should  extend  through  the  ceiling,  so  as  to 
carry  out  the  warm  air  as  it  rises.  Ventilators  8  by 
8  or  10  by  12  inches,  made  of  wood,  are  very  satis- 
factory. These  should  be  provided  with  a  roof  to  keep 
out  rain  and  at  the  bottom  end  with  a  tight-fitting 
shutter,  which  can  be  closed  in  cold  weather.  The 
ventilators  in  the  floor  may  be  holes  12  by  12  inches, 
but  they  should  be  provided  with  wire-netting  screens 
and  tight-fitting  covers  that  they  may  be  closed  when 
necessary. 

"  The  arrangement  of  the  interior  of  the  house 
depends  upon  the  methods  of  storage  used.  Some  grow- 
ers store  the  potatoes  in  boxes,  crates,  baskets,  or  hamp- 
ers, while  others  store  in  bins.  The  smaller  containers 
are  to  be  preferred  to  bins  where  it  is  practicable  to 
use.  them,  because  they  eliminate  considerable  hand- 
ling and  reduce  the  amount  of  decay.  Many  growers 
store  in  the  hampers  that  are  to  be  used  for  marketing 
the  potatoes.  This  is  a  satisfactory  plan,  as  it  requires 
no  outhiy  of  money  for  storage  receptacles,  and  the 
packages  for  shipping  must  be  provided  in  any  event  if 
the  crop  is  to  be  marketed.  Some  growers  have  bushel 
boxes  made  for  the  special  purpose  of  storing  sweet 


Harvesting  and  Storage 


195 


potatoes,  while  others  employ  various 
crates.  In  using  any  type  of 
sary  to  provide 
means  for  ventila- 
tion. A  false  slatted 
floor  is  often  made 
by  nailing  1  by  4  or 

1  by  6  inch  boards  to 

2  by  4  inch  scantling. 
An  inch  space  should 
be  left  between  the 
boards  to  allow  the 
circulation  of  air. 
A  little  space  should 
be  left  between  the 
stacks  of  boxes,  bas- 


FiGURE  27. —  Floor  plan  of  a  small 
sweet  potato  storage-house  (12x16 
feet)  suitable  for  a  farmer  who  has 
300  to  500  bushels  of  sweet  potatoes 
to  store. 


FiGtJKE  28. —  Floor  plan  of  a  20  by  40  foot  sweet  potato  storage- 
house  having  a  capacity  of  2,000  to  2,500  busiiols. 

kets,   crates,    or   hampers.     Where  these   smaller   con- 
tainers are  used,  especially  when  the  same  package  is 


196 


The  Sweet  Potato 


employed  for  shipping  the  crop,  it  is  much  easier  to 
disinfect  the  storage  house  by  spraying  than  when 
bins  are  nsed.  Another  advantage  in  using  them  is 
that  when  decay  sets  in  it  usually  spreads  only  to  the 
potatoes  in  the  single  package,  whereas  in  the  bin  it 
might  spread  throughout  the  entire  pile. 

"  If  the  bins  are  to  be  used,  the  interior  of  the  storage 
house  should  be  arranged  for  convenience  in  handling 
sweet  potatoes.  A  passage  way  about  31/2  to  4  feet 
in  width  is  usually  left  between  the  rows  of  bins, 
or  between   the  wall    and   the  bins   in   a   house   with 


FiGUKE  29. —  Floor  plan  of  a  24  by  60  foot  sweet  potato  storage- 
house  having  a  capacity  of  about  5,200  bushels. 

only  one  row  of  bins.  Sufficient  open  space  must  be  left 
to  allow  access  to  the  ventilators  in  the  corners  of  the 
storage  rooms.  Satisfactory  arrangement  of  passage- 
ways and  bins  are  shown  in  the  floor  plan  of  Figs.  29 
and  30. 

"  The  bins  are  made  as  follows:  For  the  comer  and 
middle  supports,  2  by  4  inch  scantlings  are  set  up, 
the  lower  end  nailed  to  the  floor  and  the  upper  to  the 
crosspieces  used  for  tying  the  sides  together.     Over  the 


Harvesting  and  Storage 


197 


198  The  Sweet  Potato 

supports,  1  by  4  inch  boards  are  nailed,  leaving  a  1-inch 
space  between  them.  The  ends  of  the  bins  parallel  with 
the  outside  wall  of  the  house  must  be  built  first,  because 
there  is  not  room  enough  to  work  between  the  bin  and 
the  outside  wall.  In  making  the  slat  false  floors,  2  by 
4  inch  scantlings  are  cut  to  go  across  the  bin  and  placed 
on  edge,  one  near  each  end  and  one  in  the  center.  To 
these  1  by  4  or  1  by  6  inch  boards  are  tacked,  leaving 
a  1-inch  space  between  them.  If  left  loose,  the  slat 
floor  racks  can  be  taken  out  when  the  house  is  cleaned 
and  disinfected  during  the  summer.  The  size  of  the 
bins  will  depend  somewhat  on  the  arrangement  and  size 
of  the  house,  but  it  is  not  advisable  to  make  them  more 
than  5  feet  wide,  6  to  8  feet  deep,  and  10  to  12  feet  long. 
There  should  be  a  6  to  12  inch  space  between  the  walls 
and  the  bins,  to  allow  a  circulation  of  air.  It  is  neces- 
sary to  slat  up  both  sides  of  the  scantlings  between  the 
bins,  in  order  to  leave  an  air  space  between  the  potatoes 
in  the  different  bins.  The  construction  here  described 
allows  a  4-incli  space  under  the  bins,  and  6  inches 
between  the  bins  and  outside  wall." 

Operation  of  the  storage-house. 

Before  filling  the  storage-house  each  season,  all 
decayed  and  mummified  potatoes  and  rubbish  should 
be  removed,  the  house  thoroughly  swept,  and  then 
sprayed  with  some  good  solution  such  as  corrosive 
sublimate,,  prepared  as  follows:  Corrosive  sublimate,  1 
part;  hydrochloric  acid,  2  parts;  water,  1000  parts. 
Corrosive  sublimate  is  very  poisonous  and  should  be 
handled  as  a  poison.  It  should  be  mixed  in  a  wooden 
vessel,  as  it  will  very  quickly  corrode  any  metal  con- 
tainer. 


Harvesting  and  Storage  199 

As  soon  as  the  house  has  been  thoroughly  cleaned  and 
disinfected,  a  fire  should  be  started  in  the  stove  to  dry 
out  the  room.  This  fire  should  be  kept  going  during 
the  entire  filling  process.  This  is  advisable  so  as  to 
dry  the  surface  moisture  from  the  potatoes  as  they  are 
brought  in.  As  soon  as  the  house  has  been  filled,  the 
doors  should  be  closed,  but  the  ventilators,  both  top  and 
bottom,  should  be  kept  open  as  much  as  possible  and  at 
the  same  time  maintain  a  temperature  of  80°.  When 
air  is  heated  it  rises  to  the  top  and  will  pass  out  through 
the  ventilators.  This  causes  a  suction  of  fresh  air  at 
the  bottom,  which  in  turn  is  heated  and  passes  out  at 
the  top,  thus  causing  a  constant  flow  of  warm  dry  air 
through  the  potatoes.  The  false  floor  of  the  bins  being 
four  inches  above  the  regular  floor  of  the  house,  the 
walls  of  the  bins  being  away  from  the  storage-house 
walls  at  both  sides  and  back,  and  the  bins  being  sep- 
arated from  each  other  with  a  two-inch  space,  free 
circulation  of  the  air  is  provided  throughout  the  house. 
This  circulation  is  absolutely  essential  if  sweet  potatoes 
are  to  be  cured  properly.  A  temperature  of  80°  to 
85°  during  the  curing  period  is  preferable,  though  in 
certain  cases  when  the  potatoes  are  unusually  wet  and 
sappy  a  higher  temperature  is  necessary.  As  soon  as 
the  potatoes  are  cured,  which  can  be  determined  by  a 
characteristic  velvety  feel  and  the  first  appearance  of 
sprouts,  the  heat  should  be  cut  off  and  the  temperature 
lowered  as  rapidly  as  possible  to  60°  F.  or  beloAV. 

A  coal  or  wood  stove  is  simple  to  operate  and  raises 
the  temperature  more  rapidly ;  at  the  same  time,  it 
carries  all  products  of  combustion  to  the  outside.  An 
oil  stove,  unless  an  unusually  high  grade  of  kerosene  is 
used,  will  sometimes  give  wick   trouble   when  left  to 


200  The  Sweet  Potato 

itself  for  several  hours,  getting  clogged  up  with  impuri- 
ties in  smoke  or  fumes.  It  is  unnecessary  to  fire  at 
night,  because  the  air  among  the  potatoes  circulates 
slowly.  The  air  in  the  open  spaces  of  the  room  is 
dry  after  a  day's  firing  and  diffusion  of  moisture  from 
among  the  potatoes  in  the  bins  or  crates  keeps  the  drying 
process  going  on  through  the  night.  The  process  may 
be  lengthened  slightly  in  this  way,  but  no  damage  seems 
to  result.  Whenever  spots  of  dampness  are  seen  on  the 
potatoes  or  on  the  walls,  ceiling,  or  stove-pipe  (when 
this  is  cold),  some  moisture  is  present  which  should  be 
driven  out.  On  the  other  hand,  however,  the  drying 
process  should  not  be  carried  too  far.  Excess  drying 
will  show  up  in  shriveling  or  other  sjnnptoms, readily 
noticeable. 

Extreme  care  should  be  taken  to  operate  the  house 
properly  during  the  entire  storage  period.  The  follow- 
ing general  rules  are  given  as  a  guide  for  this  process, 
which  will  necessarily  have  to  be  supplemented  by  the 
judgment  of  the  operator  to  meet  existing  conditions  in 
his  individual  case: 

1.  Avoid  temperature  below  40°  F.  as  potatoes  are 
easily  injured  by  cold(  proper  temperature  can  be  main- 
tained by  regulating  ventilation  at  doors,  windows,  and 
ventilators).  Occasionally  in  exceedingly  cold  weather 
a  little  fire  in  the  stove  may  become  necessary. 

2.  Proper  ventilation  is  essential.  On  bright  warm 
days  when  the  sun  is  shining,  windows,  doors,  and  ven- 
tilators may  be  left  open;  while  in  damp  rainy  weather 
moisture  should  be  kept  out  of  the  house  as  much  as 
possible  by  keeping  these  openings  closed. 

3.  Keep  the  house  dry.     If  moisture  collects  on  the 


Harvesting  and  Storage  201 

ceiling  or  walls,  a  fire  should  be  started  immediately  and 
sufficient  ventilation  given  to  dry  the  moisture  out  of 
the  house. 

4.  Except  in  unusual  cases  do  not  sort  potatoes 
after  they  have  been  stored  with  hopes  of  stopping  the 
decay,  for  in  so  sorting  some  sound  potatoes  will  be 
bruised  and  the  diseased  spores  on  the  decayed  and 
decaying  potatoes*  will  be  scattered  into  the  air  and 
carried  through  this  medium  to  the  sound  potatoes  which 
have  been  bruised  in  resorting.  Thus  in  a  few  days 
as  many  decayed  potatoes  will  be  found  in  the  resorted 
bin  as  before  they  were  assorted.  If  potatoes  have  been 
properly  cured,  even  though  one  potato  in  the  center  of 
the  bin  rots,  it  is  not  likely  to  contaminate  the  potato 
next  to  it. 

Outbuildings  for  storage-houses. 

Some  of  the  most  successful  sweet  potato  storage- 
houses  are  old  tenant  houses,  cribs,  or  other  outbuild- 
ings that  have  been  converted  at  small  cost.  This  prac- 
tice is  very  practicable  and  can  often  be  done  with  a 
small  outlay  of  capital.  Thus,  proper  storage  facilities 
are  brought  in  reach  of  everyone.  In  remodeling  old 
houses,  care  should  be  taken  to  have  the  walls  double 
and  tight,  so  as  to  obtain  a  dead  air  space  between  the 
walls.  The  building  should  be  ceiled,  the  ceiling  cov- 
ered with  building  paper  and  recoiled  with  1  by  4  inch 
tongue-and-groove  ceiling,  or  flooring.  In  converting 
brick,  concrete,  or  stone  houses,  it  will  be  best  to  build 
a  tight  wooden  wall  several  inches  from  the  masonry 
wall  and  then  proceed  with  the  bin  construction  as  if  the 
house  were  wooden  throughout.     In  constructing  the 


202  The  Sweet  Potato 

ventilators  in  a  remodeled  house,  it  is  sometimes  incon- 
venient to  have  the  bottom  ventilators  in  the  floor.  In 
such  cases  they  may  be  placed  in  the  side  of  the  wall  as 
near  the  floor  as  possible.  This  plan  is  not  as  good  as 
having  the  ventilators  in  the  bottom  of  the  floor,  because 
a  wind  blowing  in  the  direction  of  the  ventilators  is 
liable  to  cause  a  draft  on  the  potatoes,  which  is  not 
advisable.  But  if  care  is  taken  to  operate  the  ventila- 
tors properly,  this  disadvantage  can  be  offset  to  a  certain 
extent. 

There  is  nearly  always  a  difference  in  temperature 
from  top  to  the  bottom  of  the  house.  This  condition 
has  been  found  to  exist  in  practically  all  storage-houses 
and  should  be  overcome  as  much  as  possible  by  the 
proper  regulation  of  top  and  bottom  ventilators.  Warm 
air  naturally  rises  to  the  top  and  unless  care  is  taken 
the  potatoes  are  likely  to  become  over-cured  at  the  top 
and  not  cured  enough  at  the  bottom  of  the  house. 

Commercial  curing-houses. 

It  will  be  noted  that  the  so-called  "  government " 
storage-house  just  described  is  operated  by  the  natural 
connection  of  air  currcnits  regulated  with  vents.  The 
problems  met  in  operating  such  houses  up  to  5,000 
bushels  capacity  are  well  worked  out  and  may  be  suc- 
cessfully solved  by  following  the  directions  given,  but 
the  very  large  houses  in  which  the  natural  connection  of 
air  currents  is  depended  on  entirely  have  not  always 
given  the  desired  results.  A  number  of  specially 
designed  commercial  houses  are  on  the  market  which 
are  said  to  provide  more  satisfactory  storage  conditions. 
Most  of  these  are  covered  by  patent  and  are  erected  for 
buyers  by  the  patent  owners.     Their  principal  merit 


Harvesting  and  Storage 


203 


lies  in  special  fanning  and  ventilating  devices  wliicli 
are  provided  and  in  tlie  more  nniform  distribution  of 
heat  secured  by  means  of  special  conduction  pipes  which 
may  be  run  to  each  bin  and  controlled  by  dampers.  The 
detail  construction  and  operation  of  these  various  patent 
houses  embrace  a  study  too  exhaustive  and  technical  to 
be  taken  up  here.  Full  descriptions  and  information 
covering  operation  may  be  secured  from  the  various 
construction  companies. 


Banking. 

Although  the  scientifically  regulated  storage-house 
already  described  is 
now  recognized  as  the 
only  safe  way  to  keep 
sweet  potatoes,  it  will 
no  doubt  be  many 
years  before  all  grow- 
ers provide  themselves 
with  these  houses.  If 
potatoes  are  to  be 
banked  (see  Fig.  31), 
the  very  best  methods 
should  be  used  in  or- 
der to  offset  as  far  as 
possible  the  many  dis-       ^^^^^  3^_^  j^^^  pil^  ^^  p^t^. 

advantages  which  will  toes  to  be  coverod  with  straw  and 
dirt.  A  very  poor  method  of  bank- 
ing potatoes. 


be  present  in  spite  of 
all  that  can  be  done. 
Thompson  ^   has  very 


ably  given   the  disadvantage  of 


storage  in  pits  and  at  the  same  time  explained  how  these 
1  Farmers'  Bull.  970,  pp.  24-5-6. 


204  The  Sweet  Potato 

disadvantages  may  be  overcome  partially  by  tlie  use  of 
scientific  methods,  as  follows: 

'*  The  main  disadvantages  in  the  pit  or  bank  method 
of  storage  are  (1)  the  large  amount  of  loss  due  to  decay ; 
(2)  the  inferior  quality  of  the  sound  potatoes,  due  to 
lack  of  proper  curing;  (3)  the  loss  on  the  market, 
because  banked  potatoes  will  keep  for  such  a  short 
period  after  being  removed;  and  (4)  the  inconvenience 
of  getting  the  potatoes  when  needed,  especially  during 
cold  or  rainy  weather.  If  it  is  impossible  to  build  a 
storage  house  the  potatoes  should  be  cared  for  in  some 
other  way,  and  it  is  much  better  to  store  in  pits  or  out- 
door cellars  than  not  to  store  them  at  all.  By  using  the 
best  methods  of  banking  known,  the  loss  by  decay  can  be 
materially  reduced  but  not  eliminated,  because  it  is 
impossible  to  control  the  moisture  and  temperature. 

"  Storage  pits  should  be  located  where  the  drainage 
is  good.  In  making  a  pit  a  little  of  the  surface  soil  is 
thrown  back  to  form  a  level  bed  of  the  size  desired.  It 
is  a  good  plan  to  dig  two  small  trenches  across  the  bed 
at  right  angles  to  each  other,  to  provide  for  ventilation 
at  the  bottom.  Lay  boards  or  place  troughs  over  the 
trenches,  and  at  the  point  where  the  trenches  cross  set 
a  small  box  on  end  to  form  a  flue  up  through  the  pile  of 
potatoes.  The  earth  floor  of  the  pit  is  covered  with 
4  or  5  inches  of  straw,  hay,  leaves,  or  pine  needles, 
and  the  potatoes  are  placed  in  a  conical  pile  around 
the  flue.  A  covering  of  straw,  hay,  or  similar  ma- 
terial is  put  on  the  pile  and  over  this  a  layer  of  soil. 
The  covering  of  soil  should  be  only  a  few  inches 
thick,  but  increased  as  the  weather  gets  cold.  Keep 
the  ends  of  the  trenches  and  flue  open  until  it  is  neces- 
sary to  close  them  to  keep  out  the  frost.     It  is  better 


Harvesting  and  Storage 


205 


FiGUEE  32. —  A  number  of  sweet  potato  banks  illustrating  the 
method  of  ventilation  by  the  use  of  troughs  at  the  top  of  each 
pile. 

to  make  several  small  pits  rather  than  one  large  one, 
because  it  is  best  to  remove  the  entire  contents  when 
the  pit  is  opened.  Fig.  32  shows  a  number  of  pits 
with  a  trough  ventilator  placed  over  tlie  top  of  each  pile 
of  potatoes. 

"  A  type  of  storage  cellar  similar  to  the  one  shown  in 
Fig.  32  is  often  used  in  the  South  for  storing  sweet 
potatoes.     This  form  of  storage  is  much  better  than 


Figure  33. —  A  type  of  outdoor  cellar  used  in  some  sections  of 
the  South  for  storing  sweet  potatoes.  The  structure  should  have 
openings  near  the  bottom  and  through  the  top  for  the  purpose 
of  ventilation. 


206  The  Sweet  i'uiaio 

pits  of  banks.  The  potatoes  can  be  cured  in  the  out- 
door cellar,  and  it  is  easier  to  get  them  when  wanted  for 
the  table  or  for  market.  A  good  type  of  outdoor  cellar 
can  be  made  as  follows :  Set  a  line  of  posts  to  form  the 
center  supports  and  on  these  posts  put  a  ridgepole. 
Against  the  ridgepole  place  one  end  of  planks,  poles,  or 
slabs,  with  their  opposite  ends  resting  on  the  ground  on 
either  side.  The  ends  of  the  inclosure  are  boarded  up, 
a  door  being  provided  in  one  end.  The  structure  is 
covered  with  sod  to  a  thickness  of  5  or  6  inches.  It  is  a 
good  plan  to  put  a  ventilator  through  the  top  and  to 
leave  two  or  three  openings  in  the  sides  near  the  ground. 
Provision  should  be  made  to  close  all  these  openings 
during  cold  or  wet  weather.  By  placing  a  small  stove  in 
the  storage  cellar  the  potatoes  can  be  cured  in  the  wav 
that  has  been  described  for  the  storage  house.  The 
potatoes  are  usually  piled  on  a  layer  of  straw,  leaves,  or 
pine  needles  placed  on  the  ground.  A  better  method  is 
to  build  a  slat  floor  a  few  inches  from  the  ground  and 
pile  the  potatoes  on  the  floor.  This  floor  will  allow  the 
circulation  of  air  under  the  potatoes,  which  will  aid  in 
curing  them." 


CHAPTER  XI 

PREPARATION  FOR  MARKET 

The  subject  of  marketing  is  one  of  great  magnitude 
and  from  a  purely  theoretical  viewpoint  is  a  difficult 
one  to  study  with  accuracy,  because  of  the  many  new 
influences  which  continually  arise  to  change  modes  of 
handling  and  disposal  of  the  crop.  Our  present  day 
civilization,  in  all  of  its  industrial  and  commercial 
activities,  is  in  a  state  of  rapid  progress  and  the  farmer 
who  keeps  abreast  of  times  in  his  marketing  methods 
must  avail  himself  of  every  opportunuity  to  become 
familiar  with  the  demands  of  his  trade  and  hasten  to 
humor  the  desires  of  those  who  buy  his  wares.  People 
do  not  mind  paying  for  what  they  want.  The  one 
great  principle  of  all  successful  selling,  which  never 
changes,  is  to  create  a  desire  for  the  commodity  to  be 
sold. 

MARKET  REQUIREMENTS 

The  first  step  to  take  in  any  marketing  program  is  to 
become  thoroughly  familiar  with  the  requirements 
expected  of  a  particular  commodity  on  the  market  on 
which  it  is  to  be  sold.  If  the  southern  markets  prefer 
and  pay  better  prices  for  a  sweet  juicy  potato  of  the 
"  yam  "  kind,  good  business  principles  would  not  justify 
the  shipment  of  the  dry  mealy  variety  into  these  sec- 
tions.    On  the  other  hand,  it  would  be  poor  judgment  to 

207 


208  The  Sweet  Potato 

grow,  for  example,  Porto  Ricos  for  New  Jersey  or  Dela- 
ware for  this  section  is  noted  for  varieties  of  exceedingly 
different  characteristics.  Growers  often  have  the  mis- 
taken idea  that  because  their  neighbors  grow  one  kind 
of  sweet  potato,  they  should  plant  a  different  variety 
to  avoid  competition.  Also,  if  a  particular  section  has 
built  up  a  reputation  for  the  production  of  select  sweets 
on  the  extra  early  market  of  a  certain  city,  it  would  be 
well  for  a  newcomer  to  fall  in  line  with  custom  until  he' 
has  at  least  had  time  to  investigate.  If  after  several 
seasons  his  experience  would  lead  him  to  believe  that  an 
extra  profit  could  be  made  by  instituting  a  change  in  the 
period  of  marketing,  he  can  make  the  change  gradually 
and  be  governed  in  his  further  actions  by  the  results 
obtained  from  his  experiments.  Often  an  individual 
grower  can  in  this  way  build  up  a  very  enviable  reputa- 
tion among  a  select  trade  of  his  personal  acquaintances. 
Such  individual  efforts  are  frequently  very  profitable, 
but  it  requires  time  and  diligence  to  acquire  such  a 
grasp  on  trade.  It  can  be  done  only  after  a  careful 
study  of  what  the  market  wants  and  faithful  work  to 
meet  the  trade  desires  in  such  a  satisfactory  and  depend- 
able manner  that  one's  competitors  will  gradually  be 
out-stripped.  Such  successes  with  sweet  potatoes  by 
using  methods  entirely  foreign  to  local  customs  are  rare. 

Varieties. 

The  question  of  varieties  is  largely  a  local  prob- 
lem, depending  on  the  conditions  and  requirements 
of  the  markets  served.  Confusion  still  exists  with 
reference  to  varieties  but  a  few  kinds  have  become 
so  prominent  and  well  known  by  continual  use  and 
widespread  recognition  that  they  may  well  be  consid- 


Preparation  for  Market  209 

ered  standard.  These  standard  varieties,  such  as 
Nancy  Hall,  Porto  Kico,  Big  and  Little  Stem  Jersey, 
Southern  Queen  or  Hayman,  and  Tolman  variety  of  Old 
Spanish,  are  usually  most  profitable  from  a  commercial 
standpoint.  If  grown  at  all,  the  less  known  kinds 
should  be  used  at  home  or  sold  on  local  markets.  Noth- 
ing will  so  quickly  gain  for  a  community  a  good  reputa- 
tion as  exclusive  shipment  of  one  variety  of  potato. 
Cooperative  associations  can  do  much  toward  standard- 
izing their  production  by  adopting  one  variety  and  re- 
quiring all  shipments  made  through  the  association  to  be 
of  this  kind.  Even  among  individuals,  it  is  better  to 
select  one  good  variety  and  grow  that  exclusively.  A 
dealer  who  offers  only  one  variety  of  plants  for  sale  will 
attract  the  attention  of  many  who  would  not  otherwise 
buy,  because  of  his  specialization.  By  state  adoption, 
through  the  agencies  of  cooperative  associations  or  state 
departments  of  agriculture,  Georgia  has  adopted  the 
Porto  Eico ;  Mississippi,  Nancy  Hall ;  Alabama, 
Triumph ;  North  Carolina,  Big  Stem  Jersey ;  and  Tenn- 
essee, the  Nancy  Hall.  In  New  Jersey,  Delaware, 
Maryland  and  Virginia,  the  Jersey  varieties  predom- 
inate. Many  considerations  must  be  taken  into  account 
in  deciding  what  variety  to  grow.  The  market  demands 
will  always  decide  the  question  in  the  end.  The  north- 
ern markets  at  present  give  preference  to  the  Jersey 
type,  or  mealy  kinds,  though  certain  varieties  grown  in 
the  South  are  now  gaining  very  rapidly  in  popularity 
in  the  northern,  eastern  and  western  cities  where  here- 
tofore they  were  hardly  known.  As  an  example  of  this 
growth  in  1915,  The  Gleason  Sweet  Potato  Association 
of  Tennessee  shipped  a  carload  of  Nancy  Hall  sweet 
potatoes  to  a  commission  house  in  Chicago.     The  com- 


210  The  Sweet  Potato 

mission  merchants  were  unable  to  dispose  of  the  potatoes 
and  wired  the  association  that  only  negroes  and  dagoes 
were  buying  them,  and  for  very  low  prices.  The  sales 
manager  went  immediately  to  Chicago  and  found  that 
the  conditions  were  as  represented.  The  car  was  finally 
disposed  of  at  1.5  cents  a  bushel.  In  spite  of  this  set- 
back, the  Association  refused  to  change  from  the  Nancy 
Hall  to  the  then  more  popular  Jersey  potato,  but  con- 
tinued its  efforts  to  get  them  introduced.  The  follow- 
ing year  a  Chicago  buyer  on  a  search  for  Jerseys  visited 
the  Association  and  asked  them  to  send  him  fifty  hamp- 
ers of  Nancy  Halls.  These  he  distributed  to  the  hotels, 
to  the  better-class  families  and  to  the  residences  of  the 
city  without  charge,  merely  to  introduce  them.  The 
following  week  he  wired  for  one  hundred  additional 
hampers  and  these  sold  very  quickly.  During  the  re- 
mainder of  the  season,  twenty  carloads  of  Nancy  Hall 
potatoes  were  sold  in  Chicago.  In  1917  Chicago  bought 
forty  carloads  of  Tennessee  Nancy  Halls  and  in  1918 
nearly  one  hundred  cars  of  the  same  variety  from  this 
Association.  Efforts  are  now  being  made  all  over  the 
South  to  build  up  a  stronger  trade  in  the  northern  and 
western  markets  for  southern  "  yam "  varieties,  and 
progress  has  been  made. 

Selling  period. 

New  Jersey  and  Delaware  growers  have  built  their 
reputation  on  the  production  of  a  select  high  quality 
potato  on  the  extra  early  market  of  the  North.  Fancy 
prices  are  received  for  this  early  crop  which  is  selected 
with  the  greatest  care.  Although  it  is  expensive  to 
cater  to  these  early  market  requirements,  the  growers 
find  it  largely  profitable.     Alabama  growers  are  endeav- 


Preparation  for  Market  211 

oring  to  do  the  same  thing  with  their  early  Triumph. 

After  the  fancy  prices  of  the  early  crop  are  lowered 
by  the  regular  harvest,  many  growers  prefer  to  store 
their  crop  and  wait  for  better  prices.  This  storage  busi- 
ness has  been  highly  developed  in  certain  districts,  the 
storage-house  owners  buying  thousands  of  bushels  and 
keeping  until  the  bulk  of  the  crop  has  been  marketed 
and  prices  again  go  up.  In  some  sections  the  operation 
of  these  storage  plants  is  financed  by  the  local  banks, 
and  in  such  cases  no  difficulty  has  been  experienced  in 
getting  their  warehouse  receipts  rediscounted  by  the 
Federal  Reserve  Banks.  Whether  or  not  storage  for 
higher  prices  will  pay  depends  entirely  on  the  loss  from 
rot,  the  shrinkage  and  increased  expense  of  handling,  as 
against  the  increased  price  received  the  following  spring. 
Individual  and  local  conditions  will  largely  be  the 
influencing  factors. 

Sweet  potatoes  on  the  extra  early  and  on  the  mid- 
winter and  spring  markets  always  bring  better  prices 
than  when  marketed  in  the  fall.  During  the  season 
1918-19,  the  Onley,  Virginia,  market  opened  on  August 
19  at  $6.50  to  $7.00  a  bushel.  The  highest  price 
reached  at  all  during  the  season  was  $7.00  on  August 
26.  On  this  same  market  barrels  were  quoted  on  Octo- 
ber 7  at  $3.75  to  $3.65.^  In  the  spring  of  the  same 
season,  April  12,  1919,  these  same  New  Jersey  and 
Delaware  potatoes  were  quoted  on  the  New  York  market 
at  $3.50  to  $4.00  a  bushel  hamper,^  which  calculated 
on  the  basis  of  net  weight  was  equal  to  about  three  times 
the  lowest  quoted  price  the  fall  before.  The  1918-19 
shipping  season  was  unusual  in  market  advances.     The 

1  Bur.  Markets,  Market  Rep.  Sheet,  May  6,  1919. 

2  Bur.  Markets,  Market  Rep.  Sheet,  April  12,  1919. 


212  The  Sweet  Potato 

difference  between  fall  and  spring  prices  is  always  con- 
siderable and  is  worthy  of  calculation  in  determining 
the  best  season  in  which  to  market. 

If  the  grower  caters  to  the  extra  early  market,  the 
earliest  varieties  should  be  grown.  In  the  South,  poss- 
ibly the  Nancy  Halls  and  Triumphs  will  come  earliest. 
The  first  mentioned  also  makes  a  good  potato  for  the 
middle  and  late  market,  but  the  latter  is  seriously  dis- 
criminated against  as  soon  as  the  yellow  varieties  come 
in.  Proper  fertilization  is  also  a  material  aid  to  the 
early  crop. 

If  the  bulk  of  the  crop  is  to  be  marketed  at  digging 
time  to  local  canning  factories,  yellow  varieties  must 
be  grown,  but  no  special  attention  need  be  paid  to  early 
strains  or  special  fertilization  for  early  production. 

^hen  the  crop  is  to  be  marketed  during  the  spring 
months  after  storing,  special  care  must  be  used  to  pro- 
vide adequate  and  efficient  storage  facilities  and  to 
avoid  loss  from  decay  by  improper  handling  and  unscien- 
tific manipulation  of  the  storage-house.  The  time  of 
selling,  whether  on  the  early,  middle,  or  late  markets, 
will  vitally  influence  all  other  operations  of  production 
and  must  necessarily  be  considered  in  devising  an  effi- 
cient marketing  system. 

Containers. 

The  Bureau  of  Markets,  United  States  Department 
of  Agriculture,  as  well  as  many  cooperative  associations 
and  private  dealers,  have  given  considerable  thought  to 
the  subject  of  a  suitable  container  for  the  sweet  potato 
which  could  be  made  standard  and  used  universally. 
Definite  headway  has  been  difficult  because:  (1)  the 
legal  weight  of  a  bushel  of  sweet  potatoes  varies  widely 


Preparation  for  Market 


213 


in  the  different  states,  (see  Table  XIII)  ;  (2)  the  weight 
of  a  measured  bushel  of  sweet  potatoes  (2150  cubic 
inches)  will  vary  10  to  18  pounds  from,  fall  to  spring 
(especially  when  kiln  dried)  ;  (3)  a  measured  bushel 
of  sweet  potatoes  will  vary  several  pounds  in  weight 
according  to  the  size  of  the  tubers  and  subsequent  close- 
ness with  which  they  are  packed ;  (4)  a  measured  bushel 
of  sweets  (even  of  the  same  size  and  at  the  same  season) 
will  vary  in  weight  according  to  the  rainfall  during  the 
late  growing  period  and  the  consequent  sappiness  of 
the  roots;  and  (5)  a  number  of  different  containers  are 
at  present  in  use  in  various  parts  of  the  country  and 
each  section  seems  to  favor  the  package  which  it  has 
adopted  by  custom. 

Table  XIII. — Legal  Weight  of  a  Bushel  of  Sweet  Pota- 
toes BY  States. 


State 

Weight 

Alabama,   Georgia,   Kentucky,   Minnesota,   Oklahoma  and 

55 

Florida,  Michigan,  Missouri,  and  Virginia • 

56 

Maryland                          .        

GO 

Connecticut,  Maine,  Massachusetts,  Mississippi,  New  Jer- 
sey, New   York,   Pennsylvania,  Rhode  Island,  Vermont 
and  Wi'^consin                              

54 

Arkansas,    Idaho,    Illinois,    Indiana,    Iowa,    Kansas,    Ne- 
braska,  Nevada,   New   ]\Ie.\ico,   Ohio,   Tennessee,   South 

50 

North  Dakota  and  South  Dakota 

4G 

Packages  versus  bulk. —  Sweet  potatoes  were  formerly 
sold  and  shipped  extensively  in  bulk  but  this  practice 
is  no  longer  permissible  even  for  short  hauls,  except 


214  The  Sweet  Potato 

when  the  roots  are  to  be  used  immediately  for  canning. 
Even  in  this  case,  proper  ventilation  mnst  be  provided. 
Shipping  in  bulk  almost  necessitates  rough  handling, 
which  bruises  the  potatoes  and  causes  them  to  decay  very 
rapidly.  When  shipped  long  distances,  bulk  potatoes, 
even  when  the  car  is  provided  with  a  false  bottom  and 
false  walls  at  the  ends,  are  difficult  to  ventilate  properly 
and  are  liable  to  heat  en  route,  causing  disastrous  losses. 

Sacks. —  Handling  sweet  potatoes  in  burlap  sacks  is 
almost  as  bad  as  loading  in  bulk.  It  permits  the  outside 
roots  to  become  bruised,  allows  the  potatoes  to  rub 
together,  thus  giving  entrance  for  decay  organisms,  and 
sacked  sweets  are  difficult  to  load  tight  in  a  car  and  at 
the  same  time  ventilate  thoroughly,  l^otwithstanding 
these  disadvantages,  several  of  the  southern  markets 
give  preference  to  the  bag.  New  Orleans  commission- 
men  will  hardly  handle  sweets  in  any  container  but  the 
90-pound  burlap  sack.  The  Memphis,  Tennessee,  mar- 
ket at  times  also  favors  this  size  and  type  containers. 
When  market  demands  justify  the  use  of  sacks,  they 
should  be  handled  with  utmost  care  to  prevent  bruising 
and  should  be  properly  loaded  to  insure  safe  delivery 
(see  page  235). 

liequirements  of  siveet  potato  contamers. —  Several 
factors  must  be  considered  in  the  selection  of  a  sweet 
potato  container.  Custom  has  established  some  pack- 
ages as  standard  and  it  is  usually  bad  business  to  go 
too  much  against  well  established  customs.  Neverthe- 
less, certain  faOts  must  be  borne  in  mind  if  the  con- 
tainer problem  is  to  be  solved  satisfactorily.  The  pres- 
ent tendency  is  to  use  gift  packages  exclusively.  Such 
containers  go  with  the  potatoes  and  must  be  considered 
as  one  of  the  costs  of  marketing.     Such  containers  as 


^.. 


Plate  VIII. —  Sweet  potato  diseases,  a  and  6,  Leaf  of  sweet  potato 
plant,  showing  the  presence  of  a  number  of  circular  leaf-blight  spots, 
c  and  d,  Leaf  of  a  sweet  potato  plant,  showing  white  spots  caused  by 
the  leaf-spot  fungus,  e  and  f,  Leaf  of  a  sweet  potato  plant,  showing 
the  white-rust  fungus,  g.  A  sweet  potato  showing  the  characteristic 
appearance  of  dry-rot. 


Preparation  for  MarTcet  315 

hampers,  baskets,  bushel  crates  and  barrels  are  custom- 
arily used  as  gift  packages.  Occasionally  a  grower  can 
collect  his  baskets  or  hampers  from  local  buyers  if  the 
goods  are  sold  with  that  understanding,  but  they  are 
ordinarily  used  only  once,  the  original  cost  being  an  im- 
portant item.  In  addition  to  being  cheap,  the  contain- 
ers should  be  attractive  as  well.  Nothing  helps  to  sell  a 
bushel  of  sweet  potatoes  more  than  a  neat  attractive 
package.  The  package  should  be  convenient  to  fill,  seal, 
and  handle.  One  of  the  most  important  items  is  to  have 
a  package  that  can  be  packed  tightly  in  a  car  to  prevent 
shifting,  and  at  the  same  time  provide  ample  ventila- 
tion. The  containers  should  be  light  in  weight  to  econ- 
omize in  freight,  express  and  handling  charges,  and 
strong  and  durable  to  prevent  breakage  in  transit. 

Kinds  of  packages. —  Sweet  potatoes  are  usually 
shipped  in  160-pound  barrels,  %-  and  1-bushel  hampers, 
or  in  1-bushel  crates.  Barrels  are  most  extensively 
employed  on  the  Atlantic  Coast,  while  crates,  which  are 
just  coming  into  prominence,  are  used  almost  exclu- 
sively in  the  South.  Hampers  are  utilized  in  the  south- 
em,  northern  and  western  sections.  Although  at  pres- 
ent one  of  the  most  popular  containers,  it  has  never 
given  satisfaction  because  it  is  too  light  to  be  durable. 

Barrels. —  Growers  of  the  eastern  states  have  used 
barrels  for  many  years.  They  are,  however,  practically 
unknown  in  the  western  areas.  The  single-headed  cloth 
top  barrel  appears  to  be  the  most  satisfactory  one  now 
in  use.  When  properly  made  and  loaded,  they  are 
sufficiently  strong  to  carry  the  weight  of  the  contents 
and  fully  protect  the  potatoes  (see  Fig.  34).  Slat, 
or  veneer  barrels  are  too  flimsy  for  sweet  potatoes ;  they 
crush  or  break  easily  and  should  not  be  used  for  any 


216 


The  Sweet  Potato 


m 


Figure  34. —  Barrel  pack  com- 
monly used  for  shipping  sweet  po- 
tatoes from   Norfolk,  Virginia. 


heavy  produce.  Many 
barrels  are  still  set  up 
in  the  factory  and 
shipped  or  hauled  to 
the  place  where  used. 
This,  of  course,  re- 
quires a  considerable 
outlay  for  freight  or 
drayage,  as  nearly  as 
many  full  barrels  can 
be  hauled  as  empty 
ones.  In  this  respect 
folding  crates  or  bas- 
kets that  can  be 
produced  in  telescope 
fashion  have  an  important  advantage  over  the  barrel. 
As  it  requires  a  comparatively  large  outlay  of  cash  to 
equip  a  shop  for  setting  up  standard  barrels,  a  number 
of  cooper  shops  have  been  established  throughout  the 
east  central  sweet  potato  growing  area.  Due  to  the  in- 
creased scarcity  of  board  and  the  high  cost  of  labor,  re- 
cent prices  have  been  almost  prohibitive  and  even  in  the 
Atlantic  Coast  sections,  other  containers  are  gradually 
replacing  the  barrel.  A  standard  sweet  potato  barrel 
should  have  the  following  specifications : 

inches 

Length  of  stave  28i/^ 

Diameter  of  heads ITVs 

Diameter  between  heads 26 

Circumference    of    bulge    (outside    measure- 
ments)    64 

Thickness  of  staves,  not  greater  than ■^q 

"  Provided  that  any  barrel  of  a  different  form  having  a 


Preparation  for  Marlet 


217 


capacity  of  seven  thousand  and  fifty-six  cubic  inches  shall 
be  a  standard  barrel."  ^ 

Hampers. —  Although  veneer  hampers  are  too  light 
for  sweet  potatoes,  their  attractive  appearance  and  con- 
venience of  handling  have  made  them  a  very  popular  con- 
tainer on  the  big  markets.  However,  the  shipper  will 
have  to  count  on  occasional  severe  losses  from  breakage 


36.—  Full     bushel 
18 14  inches  liigh. 


Figure  35. —  Seven-eighths 
bushel  hamper,  16  inclies  high, 
one  of  the  most  popular  con- 
tainers for  marketing  sweet 
potatoes. 

in  transit,  even  with  the  most  careful  packing.  If 
market  demands  and  convenience  justify  the  use  of 
hampers,  they  should  be  loaded  on  end  with  alternate 
baskets  inverted  and  packed  with  the  greatest  care  (see 
page  23G).  Two  sizes  are  used:  the  yg-bushel  and  the 
full  bushel  hamper.  Manufacturers  usually  make  the 
full  bushel  hamper  I8I/2  inches  high  with  a  capacity  of 
about  2150  cubic  inches.  They  are  made  of  light  hard- 
wood veneering,  fastened  together  with  wire  staples 
1  Farmers'  Bull.  1050,  p.  18. 


218  The  Sweet  Potato 

and  furnished  with  covers  fastened  with  wire.  The  %- 
bushel  hamper  is  a  duplicate  of  the  full  bushel  except 
in  height  and  the  manner  in  which  the  top  is  fastened, 
hooks  being  used  instead  of  wire.  The  %  lacks  21/2 
inches  of  being  as  tall  as  the  full  bushel  size.  (Figs. 
35,  36). 

Crates. —  Marketing  specialists  who  have  long  been 
seeking  a  satisfactory  solution  to  the  container  problem 
for  sweet  potatoes  have  looked  with  expectancy  to  the 
crate  in  one  form  or  another  to  answer  the  question. 
A  rectangular  crate  when  properly  made  is  attractive, 
is  easily  ventilated,  is  convenient  to  handle,  packs  well 
in  a  car,  and  can  be  made  strong  enough  to  hold  up 
without  breakage.  The  convenient  lumber  supplies  and 
the  manufacturing  facilities  of  the  southern  states  also 
make  the  crate  a  very  economical  package  to  use.  The 
crate  can  be  shipped  folded  or  knocked  down  and  is, 
therefore,  economical  of  transportation  charges.  Grow- 
ers can  often  make  their  own  crates  economically  when 
suitable  material  is  convenient.  The  objection  to  the 
crate  at  the  present  time  is  that  it  is  now  little  known 
in  the  principal  markets,  and  sometimes  does  not  bring 
the  prices  commanded  on  the  same  market  by  a  better 
known  container.  This  objection  is,  however,  being 
very  rapidly  overcome  by  its  introduction  on  the  big 
markets  by  the  southern  states  and  shipping  associations. 
During  the  season  of  1917-18  and  1918-19,  Georgia 
established  a  reputation  on  the  world  markets  with  her 
"kiln-dried  Georgia  Porto  Ricos  in  50  pound  crates." 
Without  doubt  this  package  is  destined  to  become  very 
popular  and  widely  used  in  the  near  future.  At  a  meet- 
ing of  shippers,  growers  and  carriers  held  in  Jacksonville, 


Preparation  for  Market  219 

Florida,  on  August  14-15,  1918,  standard  containers 
were  adopted  for  a  number  of  commodities,  including 
a  standard  crate  for  sweet  potatoes.  As  this  package 
was  recommended  by  the  Bureau  of  Markets,  United 
States  Department  of  Agriculture,  and  is  representative 
of  the  general  type  of  rectangular  crate  now  on  the 
market,  the  following  specifications  are  given: 

"  Specifications  of  Standard  Crate, 

Dimensions :     12  X  12  X  15  inches  inside  measurement. 

Capacity  :     21(30  cubic  inches. 

Heads:  Two  heads,  solid  (12  X  12  inches),  not  less  than 
i%g  inch  thick,  made  in  one  or  tWo  pieces  stapled  together, 
or  panel  heads  made  of  head  sticks  not  less  than  i%g  inches 
thick  and  IVi  inches  wide. 

Panels :  Two  end  panels  made  of  one  piece  not  less  than 
%g  inches  thick,  securely  nailed  to  head  sticks  with  not  less 
than  4  ISTo.  16  gauge  yg  inch  wire  nails,  top  and  bottom, 
and  not  less  than  3  No.  16  gauge  "%  inch  wire  nails  across 
the  sides  (total  ten  nails).  The  veneer  may  be  stapled  with  8 
double  pointed  staples  %  inch  long  made  from  No.  18  gauge 
wire. 

Slats  (Top,  sides  and  bottom)  :  Twelve  slats,  three  each 
on  top,  bottom  and  sides,  not  less  than  Sy2  inches  wide,  ^A 
inch  thick  and  17  inches  long,  stapled  together  with  cross 
cleats  at  each  end,  each  ^g  inches  thick  and  iVz  inches 
wide,  using  No.  20  gauge  wire. 

Making  up :  Top,  sides  and  bottom  must  be  securely 
nailed  with  not  less  than  six  cement  coated  4d  nails  in  each 
end,  two  in  each  slat. 

Wood:  Veneer  or  sawed.  To  be  of  seasoned  pine  or 
gum  or  wood  of  equal  strength,  free  from  injurious  knots. 

Note  :  When  sweet  potatoes  are  shipped  in  this  crate,  the 
slats  must  be  3  inches  wide." 

Various  other  crates  are  on  the  market  which  indus- 
trial manufacturers  and  growers  claim  to  have  special 
merit.     Figs.  37  and  38  show  a  type  of  folding  crate 


220 


The  Sweet  Potato 


which  is  very  popular.     The  ends  and  sides  are  fastened 
together  with  strong  wire  hinges,  and  when  the  bottom 

is  dropped  into  posi- 
tion and  the  top  put 
on,  the  box  is  rigid 
and  durable.  The 
boxes  are  shipped 
folded  flat.  In  set- 
ting up  the  boxes,  no 
nails,  tacks,  or  metal 
fasteners  of  any  kind 
are  used.     It  is  only 


^^^"''"~ 

%m 

IM^^ 

N^^ 

^^^si^^ 

Figure  37.—  Universal  folding  box,  a 
very  substantial  patented  crate. 


necessary  to  place  the  narrow  strip  under  the  hinges  at 
one  end  of  the  box  ta  fasten  the  top  securely.  This  type 
of  box,  of  which 
there  are  several 
brands  on  the 
market,  is  pat- 
ented and  usu- 
ally costs  a  little 
more  than  the  or- 
dinary standard 
shipping  crate. 
Fig.  39  shows  an 
octagonal  shaped 
crate  which  is 
sometimes    made 


>  1  H 

1^ 

Figure  38. —  Showing  universal  fold- 
ing crate  before  bottom  is  placed  and 
standing  on  end  after  placing  bottom  in 
position. 


at  home  and  used  for  shipping  sweets.  It  is,  however, 
little  known  on  the  markets,  and  only  in  special  cases 
where  lumber  is  cheap  would  it  be  profitable.  By  refer- 
ence to  Table  XIII  it  will  be  seen  that  it  is  absolutely 
impossible  to  make  a  crate  that  will  hold  a  bushel  of  po- 


Preparation  for  Marl-et 


231 


tatoes  by  weight.  The  Bu- 
reau of  Markets  favors  the 
establishment  of  a  standard 
bushel  crate  by  volume  to  the 
one  adopted  by  the  Jackson- 
ville meeting  in  1018.  If 
this  crate  is  rather  small,  one 
containing  one-half  bushel  by 
volume  could  also  be  used. 
On  some  of  the  markets,  such 
as  Denver,  Colorado,  100- 
pound  crates  are  sometimes 
seen,  but  in  the  eastern  mar- 
kets barrels  are  commonly 
employed  when  a  container  is 
desired  holding  more  than  one  bushel.  More  standard- 
ization of  the  containers  in  shipping  sweet  potatoes  is 
needed,  and  such  standardization  can  only  be  brought 
about  on  a  volume  basis. 


Figure  39. —  Octagonal 
shipping  crate  for  sweet 
potatoes. 


PROPER  PRODUCTION 

When  the  individual  has  determined  to  his  own  satis- 
faction the  best  varieties  or  variety  to  grow,  the  season 
of  the  year  in  which  the  potatoes  will  net  the  biggest 
return  and  the  kind  of  container  which  seems  best 
suited  to  his  individual  needs,  he  has  found  out  the 
actual  requirements  of  his  market.  In  other  words,  he 
has  discovered  the  technique  of  the  marketing  business. 
]\Iarketing  really  begins  with  production.  Unless  the 
producer  can  put  into  his  stock  the  desirable  quality; 
unless  he  grows  a  quantity  sufficient  to  enable  him  effi- 
ciently to  utilize  his  labor  and  equipment,  and  to  supply 
his  market  demands;  unless  his  potatoes  are  properly 


222  The  Sweet  Potato 

harvested,  handled  to  prevent  bruising,  and  graded  or 
culled  according  to  trade  requirements,  he  has  not  solved 
his  marketing  problems.  The  grower  must  know  how 
to  produce  the  finished  article  in  the  most  profitable 
manner  possible  if  he  is  to  reap  the  rewards  of  a  well- 
rounded  marketing  system. 

Quality. 

All  trade  admires  superior  quality.  The  actual 
"  velvet  "  received  on  a  transaction  involving  a  large 
shipment  of  sweet  pota-toes  is  often  realized  entirely  on 
the  degree  of  superiority  which  the  shipment  in  ques- 
tion possesses  over  the  average  market  quality.  Qual- 
ity includes  every  factor  which  makes  the  goods  more 
attractive  and  desirable  because  of  uniformity,  grade,  or 
edible  characteristics.  The  Eastern  Shore  of  Virginia 
Produce  Exchange  has  built  up  for  itself  a  very  enviable 
reputation  for  the  quality  of  its  "  Star  Brand  "  Irish 
potatoes,  and  this  same  Association  is  doing  much  for 
the  sweet  potato  industry  in  that  section.  Individuals 
and  cooperative  associations  need  to  set  for  themselves 
a  certain  standard  of  excellence  and  always  live  up  to 
this  standard.  This  is  the  only  way  to  gain  a  reputation 
for  honesty,  fair  dealing  and  superior  quality.  Many 
of  the  New  Jersey  and  Delaware  growers  take  great 
pride  in  cultivating  this  special  fancy  trade,  and  the 
same  may  be  said  of  individuals  throughout  the  South 
and  Central  West. 

The  quality  of  a  sweet  potato  is  materially  influenced 
by  the  type  of  soil  on  which  it  is  grown,  the  rainfall, 
the  variety,  fertilization,  cultivation,  harvesting,  curing, 
subsequent  handling  and  grading.     All  of  these  sub- 


Preparation  for  Marhet  223 

jects  have  been  fully  discussed  in  other  parts  of  this 
work  except  the  handling  and  grading,  which  will  be 
treated  in  the  following  pages. 

Grading.     (See  Fig.  40.) 

The  sweet  potato  root  which  brings  the  highest  price 
on  the  markets  is  of  medium  size,  smooth  and  uniform 
and  spindle-shaped,  that  is,  long,  and  tapering  from  the 
middle  towards  both  ends.  The  roots  of  varieties 
should  never  be  mixed.  For  all  practical  purposes  the 
average  farmer  will  use  only  two  grades  roughly  classed, 
(1)  those  to  be  marketed,  and  (2)  those  used  at  home. 
When  sold  to  a  canning  factory,  the  potatoes  are  usually 
taken  "  field  run  "  and  do  not  require  grading.  Sweet 
potatoes  for  the  general  market  should  not  be  less  than 
1^  nor  more  than  4  inches  in  diameter,  and  not  more 
than  7  inches  long.  The  following  grades  on  sweet 
potatoes  which  were  temporarily  adopted  by  the  State 
Department  at  Austin,  Texas,  August  16,  1918,  have 
furnished  the  basis  of  all  attempts  for  standard  grades 
made  since  that  time: 

"  No.  1.  This  grade  shall  consist  of  sound  sweet  pota- 
toes of  similar  varietal  characteristics  which  are  prac- 
tically free  from  dirt  or  other  foreign  matter,  frost- 
injury,  bruises,  cuts,  scars,  cracks  and  damage  caused 
by  diseases,  insects  or  mechanical  means.  The  diameter 
shall  not  be  less  than  one  and  three-fourths  inches  nor 
more  than  three  and  one-half  inches. 

"  Five  percentum  by  weight  of  any  lot  may  be  below 
the  least  or  above  the  greatest  diameter  prescribed,  and, 
in  addition,  five  percentum  by  weight  of  such  lot  may  be 
below  the  remaining  requirements  of  the  grade. 


324  The  Sweet  Potato 

"  'No.  2.  This  grade  shall  consist  of  sound  sweet  pota- 
toes of  similar  varietal  characteristics  not  meeting  all 
the  requirements  of  grade  No.  1  which  are  free  from 
serious  damage  caused  by  dirt  or  other  foreign  matter, 
frost-injury,  heat  decay,  bruises,  cuts,  scars,  dry  rot  or 
other  diseases,  insects  (including  weevils)  or  mechanical 
means.  The  diameter  shall  not  be  less  than  one  and 
one-half  inches. 

"Five  percentum  by  weight  of  any  lot  may  be  less 
than  the  diameter  prescribed,  and  in  addition,  five  per- 
centum by  weight  of  such  lot  may  be  below  the  remain- 
ing requirements  of  this  grade. 

"  '  Sweet  Potatoes  '  include  yams. 

"  '  Practically  free '  means  that  the  appearance  shall 
not  be  injured  to  an  extent  readily  apparent  upon  casual 
examination  of  the  lot  and  that  any  damage  from  the 
causes  mentioned  can  be  removed  by  the  ordinary 
processes  of  paring  without  appreciable  increase  in 
waste  over  that  which  would  occur  if  the  sweet  potatoes 
were  perfect. 

"  '  Diameter '  means  the  greatest  dimension  at  right 
angles  to  any  portion  of  a  central  line  running  through 
the  sweet  potato  from  stem  end  to  root  end. 

"  ^  Free  from  serious  damage  '  means  that  the  appear- 
ance shall  not  be  injured  to  the  extent  of  more  than  20 
percentum  of  the  surface,  and  that  any  damage  from 
the  causes  mentioned  can  be  removed  by  the  ordinary 
process  of  paring  without  increase  in  waste  of  more  than 
ten  percentum  by  weight  over  that  which  would  occur  if 
the  sweet  potato  were  perfect." 

A  number  of  attempts  have  been  made  to  design  a 
practical  sweet  potato  grader,  but  thus  far  all  efforts 


Preparation  for  Marl-et 


225 


Figure  40. —  An  easily  con- 
structed potato  grader. 


have  been  futile  and  the  best 
means  of  grading  now  known 
is  with  the  hands.  A  me- 
chanical grader  is  rendered 
difficult  of  design  because  of 
the  oblong  rather  than  round 
shape  of  the  sweet  potato, 
and  the  ease  with  which  these 
roots  are  bruised  by  handling. 
The  construction  of  a  rather 
ingenious  grader  to  be  oper- 
ated by  means  of  a  sieve  of  braided  belts  was  at  one  time 
undertaken  by  an  employee  of  the  Unite'd  States  Bu- 
reau of  Markets,  but  for  some  reason  was  never  com- 
pleted. 

Quantity. 

A  consideration  which  must  enter  into  the  calcula- 
tions in  formulating  a  well-balanced  marketing  system 
through  the  production  end  is  the  question  of  quantity. 
A  farmer  should  never  grow  more  potatoes  than  he  can 
efficiently  handle  or  his  available  market  will  absorb. 
At  the  same  time,  he  must  grow  enough  to  supply  his 
profitable  trade  and  keep  his  labor,  team  and  capital 
busy  in  such  a  way  that  the  cost  of  providing  a  bushel 
will  be  reduced  to  a  minimum.  If  all  of  the  potatoes 
are  to  be  marketed  when  dug,  the  amount  to  grow  will 
depend  almost  entirely  on  the  harvesting  period,  the 
absorption  power  of  the  market  at  that  time,  and  the 
labor  which  will  be  available  when  harvest  time  arrives. 
If  adequate  sto-rage  facilities  are  available,  the  potatoes 
can  be  handled  much  faster,  in  greater  quantities  and 


226  The  Sweet  Potato 

with  less  danger  of  loss  from  growing  more  than  can  be 
marketed  immediately  than  when  such  facilities  are 
absent.  The  distance  to  the  railroad,  the  possibility  of 
securing  cooperation  from  neighbors,  available  team, 
condition  of  the  roads,  distance  from  loading  point  to 
destination  and  expense  will  all  be  vitally  influencing 
items  in  properly  regulating  the  quantity  production 
side  of  the  business. 

Storage. 

Inasmuch  as  storage  often  enables  one  to  receive 
double  the  price  for  sweet  potatoes,  it  constitutes  a  very 
important  phase  of  profitable  marketing.  It  is  also 
common  knowledge  that  well-cured  sweets  are  superior 
in  eating  quality  to  those  which  are  not  kiln-dried.  The 
buying  public  recognizes  this  fact  and  such  stock  is 
given  preference  by  the  big  markets. 

Storage-houses  often  render  handling  more  econom- 
ical and  profitable  because  of  the  ease  with  which 
potatoes  may  be  placed  in  storage  and  then  packed  and 
shipped  out  at  some  later  date  when  farm  labor  is  not 
so  much  needed  in  routine  crop  hai*vesting  operations. 

PACKING    OPEKATIONS 

The  proper  time  to  grade  sweet  potatoes  is  in  the 
field  at  digging  time.  If  to  be  kiln-dried,  grading  may 
be  facilitated  by  storing  in  crates  which  may  be  taken 
directly  to  the  field  and  the  various  grades  placed  in 
separate  crates  and  hauled  to  storage  without  further 
handling.  Even  when  handled  in  this  way,  the  potatoes 
should  be  resorted  before  shipping  out  the  following 
winter  or  spring.  This  should  be  done  by  placing  the 
roots  directly  into  the  containers   in  which   they  are 


Preparation  for  Marl-et 


227 


fe^^^ 

i#i 

..J^^ayM./  /y/^ 

shipped,  as  they  are  taken  from  the  storage  crates. 
Every  care  must  be  used  to  prevent  bruising  in  all  hand- 
ling operations,  as  such  blemishes  give  an  opportunity 
for  bread  mold,  or  soft-rot  to  set  in.  Containers  must 
be  chosen  for  their  carrying 
quality  and  economy  in  the 
sense  of  properly  protecting 
the  potatoes  from  injury. 

In  packing  barrels,  no  espe- 
cial care  in  filling  is  neces- 
sary as  in  the  case  of  apples 
or  other  fruit,  but  the  rock- 
ing should  be  done  about 
three  times  during  the  pro- 
cess of  filling  to  insure  a  good 
pack  and  full  measure  (Fig. 
41).  As  the  process  of  fill- 
ing progresses,  the  barrel  is 
gently  rocked  back  and  forth  to  settle  the  roots  well  down 
as  closely  together  as  possible.  This  process  is  started 
by  placing  the  barrel  on  a  plank  about  two  inches  less 
in  width  than  the  diameter  of  the  barrel,  instead  of 
using  a  follower  to  hold  down  the  potatoes  and  inserting 
a  head,  or  as  is  sometimes  done  with  Irish  potatoes  and 
frequently  in  packing  various  fniits,  the  barrel  is 
slightly  hooped,  or  as  is  known  in  fruit-packing  bilged. 
The  burlap  cover  is  usually  secured  by  having  it  covered 
by  the  top  loop.  If  the  barrel  has  been  properly  packed 
and  rocked,  1  to  II/2  inches  bilge  will  insure  a  full 
barrel  on  arrival  at  destination.  If  the  bilge  is  too 
much,  the  top  layer  of  potatoes  will  be  so  badly  bruised 
in  transit  that  they  will  decay  rapidly  when  opened. 


Figure  41. —  Sweet  potato 
barrels  and  device  for  press- 
ing the  heads  into  place. 


228  The  Sweet  Potato 

Growers  who  are  workinc;  np  fancy  trade  sometimes  use 
paper  lining  around  the  inside  of  the  barrel,  with  corru- 
gated paper  caps  on  the  ends.  These  caps  are  sup- 
posed to  prevent  bruising.  Lace  circles  of  paper  are 
often  placed  on  top  to  make  the  barrel  more  attractive 
when  exposed  for  sale.  These  frills  are,  however,  un- 
called for  and  with  sweet  potatoes  more  than  any  other 
fai-m  crop  superb  quality  of  the  product  with  neat  and 
substantial  packing  will  in  the  end  prove  most  profitable. 
In  packing  hampers  or  crates,  there  is  less  tempta- 
tion to  bruise  the  potatoes  by  dropping  into  the  contain- 
ers than  is  true  of  barrels.  Sweet  potatoes  should  be 
lifted  from  one  container  and  placed  as  carefully  in 
another  as  in  handling  eggs.  It  is  remarkable  the  speed 
that  can  be  acquired  with  a  little  practice  and  at  the 
same  time  handle  the  roots  in  such  a  manner  that  they 
will  not  be  bruised.  Hampers  or  bushel  crates  should 
be  packed  tightly  with  about  •'^-inch  bilge.  A  full 
bushel  hamper  or  crate  holding  2150  cubic  inches  will 
hold  50  to  52  pounds  of  No.  1  sweet  potatoes  after  they 
have  been  cured,  if  tightly  packed.  Most  growers  try 
to  put  51  pounds  into  a  package  of  this  kind,  calcu- 
lating that  it  will  contain  about  50  pounds  net  when  it 
reaches  the  consumer.  The  appearance  of  packs  can 
be  greatly  enhanced  if  careful  facing  is  done.  By 

facing  is  meant  the  special  placing  of  the  top  layer  of 
potatoes  to  insure  a  smooth,  even  and  attractive  sur- 
face. Facing  is  not  a  means  of  defrauding  the  buyer 
by  placing  potatoes  of  one  grade  on  top  and  inferior 
grades  on  the  bottom  and  selling  the  whole  on  the  basis 
of  the  top  quality,  but  consists  in  the  systematic  arrange- 
ment of  the  top  layer  of  potatoes  so  that  the  appefirance 
will  be   pleasing.     Proper  facing  not  only  assists   in 


Preparation  for  MarVei  229 

selling  but  prevents  undue  bruising  of  potatoes  that 
might  otherwise  be  projecting  above  the  average  level 
of  the  pack. 

Crates  or  hampers  which  hold  a  bushel  are  quite  con- 
venient to  handle  and  make  attractive  packages.  The 
objection  sometimes  heard  to  the  crate  is  that  if  there 
is  a  small  or  off-grade  potato  in  the  package  it  will  be 
more  readily  seen  than  with  the  hamper.  This  is  no 
doubt  true  but  should  not  be  a  serious  objection,  as  it 
enables  the  buyer  to  see  exactly  what  he  is  getting  and 
encourages  the  strictest  honesty  and  careful  grading  on 
the  part  of  the  shipper.  The  very  defect  provides  an 
advantage  in  giving  better  ventilation. 

PKOPER    TRANSIT 

After  the  requirements  of  the  market  have  been  care- 
fully determined  and  after  all  the  attendant  troubles 
of  production  have  been  effectually  overcome,  the  pota- 
toes safely  stored  until  the  prices  are  attractive,  and 
then  perfectly  packed  in  the  most  secure  and  attractive 
manner  possible,  the  business  will  be  a  failure  if  the 
product  is  not  gotten  to  market  in  salable  form.  The 
difference  between  profit  and  loss  is  often  incurred  in 
forty-eight  hours  from  injuries  in  transit  that  have  been 
avoided  for  months  on  the  farm  and  in  the  storage- 
house.  Often  these  injuries  represent  losses  that  could 
have  been  avoided  had  proper  attention  been  paid  to: 
(1)  selecting  the  type  of  car  best  suited  for  the  ship- 
ment at  season  in  which  it  was  made  and  for  the 
specific  distance  which  the  car  was  to  cover  before 
reaching  destination;  (2)  correctly  packing  the  car 
with  the  special  containers  used;  (3)  proper  regula- 
tion of  ventilators  in  transit.     The  goods  must  reach  the 


330  The  Sweet  Potato 

cousumer  in  usable  condition  if  profit  is  to  result. 
Even  when  goods  are  sold  f.  o.  b.  the  track,  the  seller 
owes  it  to  his  customer  to  take  every  possible  precaution 
to  insure  him  a  safe  delivery.  Sweet  potatoes  are  ex- 
tremely perishable  and  intelligence  is  essential  in  pro- 
viding proper  accommodations  in  transit.  Further- 
more, the  way  in  which  a  car  is  packed  has  much  to 
do  with  the  commission  merchants'  possibility  of  dis- 
posing of  it  profitably  at  the  other  end  of  the  line. 

Choice  of  car. 

Four  types  of  freigbt  cars  may  be  used  for  shipping 
sweet  potatoes  to  market:  (1)  the  common  freight  car; 
(2)  the  air-ventilated  cars;  (3)  the  refrigerator  cars; 
and  (4)  the  heated  cars. 

The  common  freight  cars  are  the  ones  in  which  ordi- 
nary merchandise  is  usually  shipped.  This  type  is  not 
well  adapted  to  the  shipment  of  sweet  potatoes  even  for 
short  hauls.  They  are  employed  only  when  a  few  crates 
or  barrels  are  shipped  along  with  other  merchandise  on 
short  freight  hauls  that  can  be  made  in  one  or  two  days. 
Occasionally  the  common  freight  is  provided  with  a 
false  bottom  and  used  for  shipping  sweets  to  canning 
factories  in  bulk,  but  even  in  such  cases  the  air-ventil- 
ated cars  arc  preferable.  Such  cars  should  never  be 
used  for  shipping  car-lot  potatoes  over  long  distances, 
for  they  are  provided  with  no  means  of  regulating  ven- 
tilation, and  in  long  hauls,  especially  with  new  potatoes, 
heating  is  almost  sure  to  occur  with  disastrous  results. 

Air-ventilated  cars  represent  tlie  type  best  suited  for 
handling  sweet  potatoes  in  all  regions  where  special  in- 
sulation is  not  necessary  to  prevent  freezing.     Such  cars 


Preparation  for  Marl-et  231 

can  usually  be  secured  as  easily  as  an  unventilatod  box- 
car, and  they  should  always  be  used  in  preference. 
These  cars  are  provided  with  two  ventilators  at  either 
end  wall  which  can  be  opened  or  closed  as  desired. 
These  vent  openings  have  iron  rods  or  heavy  iron  cloth 
to  prevent  stealing  when  the  doors  are  open.  Though 
not  regularly  furnished  with  a  false  bottom,  such  a  floor 
should  always  be  installed  when  shipping  long  distances 
and  for  short  shipments  when  the  potatoes  are  bulked. 
A  false  bottom  can  be  constructed  of  rough  lumber  for 
about  1  cent  a  bushel  capacity  of  the  car,  and  is  very 
cheap  insurance.  In  installing  such  false  floors,  care 
should  be  taken  to  have  the  runners  placed  lengthwise 
the  car  with  floor  strips  crossways,  and  to  see  that  the 
under  air  passage  formed  is  not  obstructed  in  any  man- 
ner, else  the  object  of  the  false  floor  will  be  defeated  (see 
Fig.  42). 

The  railroads  will  supply  refrigerator  cars  for  per- 
ishable or  semi-perishable  shipments  to  the  extent  of 
their  ability,  preferably  for  longer  runs.  These  cars 
should  always  be  used  in  shipping  sweet  potatoes  to 
the  northern  markets,  as  the  special  insulation  prevents 
freezing  and  the  top  ventilators  in  each  end  provide 
ample  circluation  of  air  as  long  as  the  car  is  in  motion. 
A  certain  percentage  of  these  cars  belonging  to  the 
various  roads  is  already  equipped  with  false  floors,  or 
floor  racks.  It  is  contemplated  eventually  to  equip 
all  of  the  cars  in  this  way.  When  not  so  equipped 
when  secured,  the  shipper  will  always  find  it  profitable 
to  put  in  these  floors  at  his  own  expense  rather  than 
ship  long  distances  with  the  bottom  ventilation  that 
would  be  provided.     During  the  war  period,  the  United 


233 


The  Sweet  Potato 


States  Railroad  Administration  issued  an  order  in  which 
they  stated  that  "  The  railroads  will  reimburse  shippers 
for  the  value  of  floor  racks  so  placed  to  the  amount  of 


Preparation  for  Marl-et 


233 


fifty  (50)  cents  per  linear  foot  of  the  total  inside 
length  of  car  "  ^  but  in  normal  times  the  shippers 
would  have  to  hear  this  expense.  No  ice  is  used  in 
refrigerator  cars  for  sweet  potatoes.  An  average  of 
about  630  hampers  can  be  put  in  a  car,  30,000  pounds 
being  considered  a  safe  load.  Thorough  ventilation  is 
an  absolute  essential  in  making  successful  shipments  of 
sweet  potatoes  in  any  type  car. 

Stock  cars  are  occasionally  used  for  short  shipments 
in  warm  regions. 


Paching  in  car. 

There  is  an  unwarranted  tendency  toward  careless- 
ness in  loading  sweet 
potatoes.  Often 
avoidable  breakage 
occurs  in  cars  care- 
fully packed.  In  ad- 
dition to  ample  ven- 
tilation, the  car 
should   be   so  loaded 

as   to   avoid   shifting  ^            ^„       .         .  ^.         ,   ^, 

p  Figure    43. —  A    variation    of    the 

01  the  load  m  transit  standard     load.     Loading     100-pound 

and    breakage    of    the  ^^^ks  so  as  to  secure  a  heavy-weight 

^  shipment  with  the  greatest  amount  of 

containers  by  contact  ventilation. 

with  each  other. 

BaiTels. —  Both  the  double-headed  ventilated  barrel 
and  the  cloth-top  barrel  should  be  loaded  on  end  rather 
than  on  their  bilge,  as  investigation  shows  that  much 
less  breakage  results.^  The  main  objection  to  loading 
on  end  is  that  when  very  tightly  packed,  owing  to  jolting 

1  Circ.  CS-43,  U.  S.  R.  R.  Adm.,  W.  G.  McAdoo,  Nov.  15,  1918. 

2  Farmers'  Bull.  Xo.  1030,  p.  !>. 


234 


The  Sweet  Potato 


in  transit,  the  barrels  may  appear  to  be  of  slack  measure 
when  they   arrive  at  the  market.     This  fault  can  be 

largely  eliminated  by 
proper  rocking  of  the 
barrel  while  tilling 
(page  227).  When 
circumstances  justify 
loading  on  the  bilge, 
headlines  should  be 
used.  When  loaded 
on  end,  five  barrels 
placed  across  the  end 
of  the  car  will  give  a 
snug  fit.  A  36-foot 
car  will  carry  105 
barrels  in  each  such  layer.  When  the  first  layer  has 
been  distributed  throughout  the  car,  strips  of  wood 
should  be  put  on  top  of  these  barrels  and  the  second 


Figure  44. —  Barrels  loaded  on 
their  bilge  crosswise  of  the  car. 
Note  that  the  barrels  on  the  fourth 
layer  should  have  been  against  the 
wall  on  the  right. 


Figure  45. —  Double-headed  ventilated  barrels  loaded  on  end. 
Strips  should  have  been  placed  between  the  layers  in  this  load. 


layer  placed  directly  on  top  of  the  first  row,  taking  care 
throughout  the  car  to  keep  the  barrels  tight  against  each 


Preparation  for  Market 


235 


Figure  4fi. —  Sacked  sweet  potatoes 
being  shipped  in  stock  car.  Plenty 
of  ventilation,  but  dangerous  on  ac- 
count  of   changes   in   temperature. 


other.  With  cloth-top  barrels,  less  briiisina;  will  per- 
haps result  if  the  top  layer  is  loaded  on  bilge.  When 
loaded  in  this  man- 
ner the  cloth-tops 
should  be  placed  to- 
ward the  inside,  par- 
ticularly in  the  door- 
way. In  old-sized 
cars  it  is  sometimes 
necessary  to  load  all 
barrels  on  bilge  which 
are  in  the  doorway  to 
insure  a  tight  fit.  In  all  cases  the  doorways  should  be 
stripped  up  with  lumber  an  inch  or  more  thick,  from  the 
inside  to  prevent  bilging  of  the  doors  or  falling  out  of 
doorways  (se'e  Figs.  43-4-5). 

Sacks. —  As  stated,  sacks  are  unsatisfactory  as  con- 
tainers but  are  still  sometimes  used.  Sacks  holding 
more  than  100  pounds  should  never  be  tolerated,  90- 
pound  bags  being 
most  commonly  used. 
Loading  sacks  in  any 
car  without  provision 
for  ventilation 
throughout  the  load 
is  inviting  loss. 
Figs.  46-48  show 
correct  and  incorrect 
ways  of  loading  sacks. 
Hampers  should  never  be  loaded  on  their  sides.  The 
practice  sometimes  followed  cannot  be  too  severely 
condemned  (Figs.  49-50).     Hampers  should  always  be 


Figure  47. —  This  car  was  not  loaded 
properly  and  did  not  carry  safely. 


236 


The  Sweet  Potato 


loaded  on  end  with  alternate 
baskets  inverted.  Every  pos- 
sible care  should  be  taken  to 
make  the  load  tight  with  no 
slack  space  either  at  ends  or 
across  the  car.  Some  grow- 
ers prefer  to  brace  the  load 
by  nailing  strips  across  the 
car  every  three  or  four  tiers 
of  hampers.  Frequently  no 
hampers  are  placed  in  the 
door,  but  each  end  of  the  car 

is  braced  separately,  leaving  the  door  space  vacant  for 

ventilation. 

Crates  may  ordinarily  be  packed  tightly  in  the  car 


Figure  48. —  Correct  way 
of  loading  sacked  sweet  po- 
tatoes. 


Figure  49. 


Breakage  and  damage  in  a  car  of  hampers  loaded  on 
their  sides. 


and  at  the  same  time  be  sufficiently  ventilated  by  plac- 
ing strips  an  inch  thick  between  layers  of  crates.  The 
crates  should  be  held  in  place  with  car  strips  and  no 
slack  space  be  left  under  any  circumstances  without 
suitable  bracing.  Especial  care  is  necessary  to  have 
the  crates  securely  tiffht  from  end  to  end  of  the  car. 


Preparation  for  Marl-et 


237 


From   600   to   700  crates  constitute   an  average  good 
load. 

Temperature  in  transit. —  The  effect  of  various 
methods  of  ventila- 
tion in  transit  and 
the  relative  influence 
of  varying  tempera- 
tures on  the  carrying 
quality  of  sweet  po- 
tatoes are  at  this 
time  under  investiga- 
tion by  specialists  of 
the  Bureau  of  Mar- 
kets. It  is  known  that  ventilation  is  essential,  that  over- 
heating is  as  disastrous,  or  more  so  than  freezing,  and 
that  temperatures  between  these  two  extremes  may  con- 
siderably influence  the  susceptibility  of  the  potatoes  to 
disease  attacks  and  decay.  Of  the  technical  details  of 
these  things,  however,  little  is  yet  knovm. 


P^ 

B|M| 

'^    ^-\^ 

f  "HS^ShHI 

X^wq 

lpffll 

^w 

w^M% 

Figure  50. —  Do  your  sweet  potatoes 
arrive  at  market  like  this? 


CHAPTER  XII 

COMMERCIAL  DISPOSAL   OF  THE  SWEET 
POTATO 

The  sweet  potato  is  now  going  throngh  the  process  of 
standardization  and  introduction  into  the  world  mar- 
kets. This  fact  will  be  appreciated  when  it  is  noted 
that  out  of  the  eighteen  states  growing  sweet  potatoes, 
those  which  produce  less  than  one-tenth  of  the  total 
crop  of  the  United  States  make  more  than  one-half 
the  total  car-lot  shipments.  Nevertheless,  marketing 
has  made  remarkable  strides  within  the  last  few  years. 
It  is  only  in  recent  years  that  the  general  sweet  potato 
grower  has  taken  any  interest  in  the  selling  of  his 
surplus  beyond  the  limits  of  his  immediate  markets. 
These  markets  have  usually  consisted  in  the  many  small 
towns  where  the  potatoes  were  occasionally  peddled  out 
on  the  streets  or  in  a  few  local  sales  in  small  quantities 
to  neighbors  less  abundantly  supplied. 

Conditions  have  changed  very  rapidly  within  recent 
years  and  sweet  potatoes  are  now  known  and  called  for 
in  many  markets  which  until  lately  have  been  in  ignor- 
ance of  this  southern  delicacy.  All  regular  market  re- 
ports now  quote  sweet  potatoes  in  season,  along  with 
other  leading  fruits  and  vegetables.  The  standardiza- 
tion of  market  conditions  and  the  fact  that  new  mar- 
kets are  continually  being  opened  up  and  old  markets 
are  capable  of  development  by  controlling  seasonal  dis- 
238 ' 


Commercial  Disposal  of  the  Siveet  Potato        239 

tribiition  and  carefully  catering  to  the  desires  of  the 
best  trade,  make  it  imperative  that  the  present  day 
grower  know  something  of  the  available  marketing 
agencies  and  familiarize  himself  with  the  best  methods 
of  manipulating  his  crop  through  the  various  chambers 
of  commerce.  The  present  tendency  is  for  the  grower 
to  take  an  active  interest  in  the  disposition  of  his  pota- 
toes and  in  many  instances  do  the  actual  selling  him- 
self. This  calls  for  good  business  judgment  in:  (1) 
choosing  the  best  markets  and  properly  developing  them ; 
(2)  cultivating  sales  in  various  markets;  (3)  properly 
weighing  the  importance  of  various  sales  factors  which 
influence  market  conditions  each  season;  and  (4)  deal- 
ing with  the  different  selling  instrumentalities  which 
commerce  will  always  make  legitimate  and  necessary. 
The  grower  must  also  know  something  of  the  terms 
and  methods  which  may  be  employed  in  transacting 
sales,  if  his  operations  are  to  be  placed  on  a  business 


At  the  present  time,  only  two  channels  of  trade  are 
opened  to  the  producer.  They  consist  of  the  "  home 
market "  and  foreign  markets.  The  latter  term  is  not 
used  to  designate  markets  outside  of  the  United  States, 
but  refers  to  all  markets  outside  of  the  state  where 
grown.  This  usually  means  shipping  to  the  eastern, 
northern,  or  middle-western  fruit-  and  vegetable-con- 
suming cities,  as  New  York,  Philadelphia,  Cincinnati, 
Chicago  or  Omaha.  At  present,  local  canning  factories 
handle  a  large  part  of  the  home  market  trade.  These 
canneries  are  now  located  in  practically  every  state 
where  sweet  potatoes  are  of  any  considerable  importance, 
and  are  playing  an  important  part  in  consuming  much 
of  the  crop  during  the  harvest  months.     Many  enthus- 


240  The  Sweet  Potato 

iastically  predict  the  development  of  an  important  ex- 
port trade  in  sweets  as  scientific  storage-houses  become 
more  widely  used. 

MARKETS 

The  markets  to  be  patronized  will  influence  to  an  im- 
portant extent  all  of  the  pre-marketing  operations  of 
the  grower.  The  requirements  of  different  markets 
should  be  studied  and  the  advantages  and  disadvantages 
of  each  carefully  compared.  This  will  necessarily  have 
to  be  learned  largely  by  experience.  Most  growers 
believe  with. good  reason  that  they  can  dispose  of  their 
crop  more  satisfactorily  in  territory  within  their  reach 
by  wagon,  provided  the  quantity  is  not  so  great  as  to 
flood  the  market.  Many  things  favor  the  home  market. 
In  practically  all  parts  of  the  South  it  has  been  the 
main  dependence  as  an  outlet  and  even  so  has  not  been 
over-supplied  when  marketing  was  distributed  over  the 
entire  year  rather  than  a  few  months  at  digging  time. 
There  is  nearly  always  a  scarcity  of  sweet  potatoes,  even 
in  the  principal  production  areas,  during  the  spring 
months.  Many  growers,  however,  do  not  yet  have 
proper  storage  facilities,  the  capital  or  the  inclination 
to  hold  their  potatoes  for  advanced  prices,  and  when 
the  home  markets  are  already  abundantly  supplied  or 
when  the  price  is  low  in  local  centers  which  are  over- 
supplied,  the  growers  must  turn  to  the  larger  cities. 
It  must  be  remembered  that  over  one-half  the  total  pop- 
ulation of  the  United  States  is  within  a  radius  of  500 
miles  of  Xew  York  City.  Consequently  this  area  has 
a  consuming  power  equal  to  all  the  remainder  of  the 
United  States  combined. 

The  location  of  a   suitable  market  is   of  first  im- 


Commercial  Disposal  of  the  Sweet  Potato        241 

portance.  Sometimes  growers  may  contract  to  produce 
potatoes  for  a  canning  factory  at  a  fixed  price,  or  the 
latter  may  guarantee  to  handle  the  growers'  output  at 
prevailing  prices  at  digging  time.  The  grower  who  is 
near  a  city  may  often  build  up  a  fancy  trade  among 
certain  families,  restaurants,  hotels,  or  fancy  stores. 
Such  a  trade  is  often  very  profitable  and  satisfactory. 
When  good  home  markets  are  not  available,  the  grower 
may  sometimes  become  acquainted  with  some  individual 
in  other  regions  who  is  able  to  handle  his  crop.  Many 
times  a  grower,  because  of  the  superiority  of  his  product, 
the  neat  appearance  of  his  packages,  or  his  care  in 
grading,  will  attract  the  attention  of  some  reliable 
broker,  wholesale  grocer  or  commission-man  in  some 
city,  and  gain  his  confidence  to  the  extent  that  each  year 
he  will  look  to  this  particular  producer  for  his  best 
stock.  The  grower  will  often  find  it  well  worth  while 
to  make  an  occasional  trip  to  market  and  become  per- 
sonally acquainted  with  the  men  who  buy  his  products. 
When  the  shipper  does  not  personally  know  some  buyer 
on  the  market,  names  of  reliable  dealers  may  be  secured 
from  the  marketing  department  of  his  state  agricultural 
college.  The  day  of  the  unscrupulous  dealer  in  town 
is  almost  over.  Any  standard  firm  or  brokerage  that 
advertises  regularly  in  the  leading  trade  journals  may 
be  dealt  with  without  fear  of  fraud.  The  grower  will, 
of  course,  have  to  use  his  own  judgment  in  the  way  he 
sells  in  any  one  instance. 

Home  marhets. 

Home  markets  offer  a  better  medium  through  which 
to  sell  than  foreign  ones.  When  potatoes  are  shipped 
to  some  distant  city,  a  commission  has  to  be  paid  to 


342  The  Sweet  Potato 

some  one  for  handling  them.  Any  possible  commission 
is  eliminated,  however,  when  the  grower  sells  directly  to 
the  consumer  on  a  home  market.  In  addition  to  this, 
many  growers  prefer  the  home  markets  because  they 
are  given  an  opjwrtunity  to  put  into  their  sales  their 
own  individuality.  They  meet  and  know  their  buyer 
personally,  become  acquainted  with  their  desires,  and 
are  better  able  to  meet  trade  requirements.  Such  per- 
sonal contact  is  also  conducive  to  improvement  and  de- 
velopment in  selling.  The  grower  thereby  learns  the 
value  of  what  would  perhaps  otherwise  seem  unimpor- 
tant details  of  efficient  salesmanship.  It  enables  him 
to  grow  with  the  increasing  demands  of  his  business. 

Frequently  when  it  is  not  convenient  or  desirable  to 
sell  direct  to  the  consumer,  it  may  be  possible  to  sell  to 
small  grocery  stores,  canning  factories,  storage  plants, 
or  local  buyers  who  assume  the  risk  of  shipping. 
Although  the  gross  price  received  from  such  sales  is 
always  less  than  from  a  private  retail  trade,  it  is  some- 
times more  than  the  net  returns  would  be  when  the  ad- 
ditional time  and  expense  involved  in  the  more  direct 
small  sales  are  figured.  Because  of  better  organized 
and  more  efficient  means  of  selling,  a  grocer  can  some- 
times pay  the  grower  a  better  net  price  than  the  latter 
could  secure  by  personally  peddling  his  potatoes.  This 
is  not  always,  or  even  frequently,  the  case,  however,  as 
dealers  who  buy  usually  allow  enough  margin  to  insure 
a  good  profit  on  such  perishable  goods.  This  is 
especially  true  of  local  buyers  who  purchase  with  an 
idea  of  shipping.  Such  men  are  usually  well  posted 
on  market  conditions  and  certainly  keep  on  the  safe  side 
of  purchasing  prices.  Commercial  storage  companies 
and  local  canning  factories  furnish  one  of  the  most  sat- 


Commercial  Disposal  of  the  Sweet  Potato       243 

isfactory  means  of  marketing  locally.  Sncli  institutions 
when  owned  and  operated  by  progressive  men  can  often 
be  the  means  of  remarkably  developing  the  sweet  potato 
industry  in  a  very  short  time.  When  sold  to  such  con- 
cerns, the  grower  can  usually  sell  in  as  large  quantities 
as  he  desires,  he  assumes  no  risk,  and  does  not  have  to 
wait  for  his  money. 

However,  when  all  of  these  advantages  have  been 
thought  over,  there  is  a  dangerous  tendency  to  yield  to 
the  most  convenient  method  at  the  expense  of  profit. 
The  grower  should  keep  well  posted  on  prevailing  mar- 
ket conditions  all  over  the  country  and  after  carefully 
calculating  the  relative  cost,  trouble  and  risk  of  selling 
on  various  markets,  dispose  of  his  goods  through  that 
channel  which  will  probably  give  the  greatest  net  return. 
A  farmer  will  sometimes  continue  selling  on  one  market 
regardless  of  price  because  of  habit  and  his  more  inti- 
mate knowledge  of  the  specific  conditions  there. 

Foreign  markets. 

When  sweet  potatoes  are  marketed  beyond  the  terri- 
torial range  possible  of  personal  attention  by  the  grower, 
some  third  party  must  be  entrusted  with  the  responsi- 
bility of  their  satisfactory  disposal.  The  transporta- 
tion lines  are  responsible  to  a  certain  extent  for  safe  de- 
livery at  destination.  This,  however,  covers  only  such 
incidents  as  can  be  charged  directly  to  the  negligence  of 
the  transportation  company,  and  does  not  relieve  the 
shipper  of  errors  in  selection  of  car  type  and  proper 
packing.  When  foreigTi  markets  are  patronized,  the 
potatoes  are  usually  handled  through  a  commission 
agency  of  some  kind  which  takes  its  pro-rata  toll  for 
the  service  rendered.     This  commission  medium  may 


244  The  Sweet  Potato 

be  the  regular  vegetable  broker  in  the  city  or  a  cooper- 
ative shipping  association,  owned  by  the  growers  them- 
selves. Snch  organizations  have  overhead  expense  that 
must  be  met  by  requiring  a  certain  percentage  of  the 
gross  sales.  When  owned  by  growers,  any  tendency 
towards  economy  of  sale  will  be  in  their  favor,  which  is 
not  true  of  privately  operated  selling  mediums  which 
must  not  only  meet  actual  expenses  but  must  make  at 
least  a  living  wage  in  profit  besides. 

Occasionally  it  is  possible  for  a  producer  to  cater  to 
a  private  trade  when  his  reputation  for  honesty,  quality 
and  fair  dealing  has  been  sufficiently  established,  even 
on  the  more  distant  markets.  In  developing  a  trade 
of  this  kind,  agreements  have  to  be  made,  often  months 
in  advance  of  delivery,  with  the  manager  of  hotels,  res- 
taurants, resorts,  clubs,  or  private  houses,  to  use  a 
certain  quantity  of  a  specified  grade  delivered  at  such 
time  as  may  be  agreed  on  between  buyer  and  seller. 
Regions  in  which  sweet  potatoes  of  the  best  quality  are 
not  well  known  offer  the  best  territories  in  which  to 
work  up  such  private  trades.  Thousands  of  individual 
growers  all  over  the  South  have  established  such  private 
trades  in  distant  cities-  by  sending  an  acquaintance  in 
the  territory  samples  of  his  most  select  roots,  requesting 
the  receiver  to  give  them  to  his  friends.  Sometimes  the 
grower  will  have  printed  on  a  neat  wrapper  his  name 
and  address  and  a  few  words  concerning  his  potatoes. 
Each  potato  may  be  wrapped  separately  in  these  papers. 
It  is  nearly  always  necessary  to  send  samples  of  the 
potatoes  to  be  sold  in  working  up  private  trades. 

With  the  advance  of  the  new  scientifically  constructed 
storage-house,  the  possibility  of  putting  sweet  potatoes 
in  storage  in  the  cities  is  destined  to  open  up  one  of  the 


Commercial  Disposal  of  the  Sweet  Potato        245 

most  important  systems  of  marketing.  If  a  company 
of  progressive  growers  could  be  organized  that  would 
build  a  chain  of  commercial  curing-plants  in  the  large 
markets,  with  managers  to  receive  the  stock,  store  it  and 
later  sell  to  the  jobbers  and  retail  trade  when  the  price 
was  sufficiently  high,  a  most  efficient  commercial  storage 
and  marketing  system  could  be  developed.  In  fact,  if 
such  a  corporation  had  sufficient  capital  and  support  of 
the  growers  over  the  country,  there  is  no  reason  why  in 
time  it  could  not  almost  control  the  entire  sweet  potato 
industry  of  this  country.  Without  doubt  the  very  near 
future  will  witness  the  growth  of  just  such  a  corporation, 
controlled  and  managed  as  are  the  big  corporations 
which  now  import  tropical  fruits. 

Some  factors  in  foreign  marketing  coincide  with  those 
of  local  marketing,  and  there  are  also  many  differences. 
It  is  instructing  to  compare  these  two  methods  of  sell- 
ing. The  commissions,  freight,  and  additional  expense 
of  packing  make  it  necessary  to  receive  a  much  larger 
price  than  can  be  obtained  at  home.  ISTet  prices  on  home 
markets,  other  things  being  equal,  are  more  often 
greater  than  the  net  returns  from  foreign  shipments. 
Competition  is  also  greater  on  the  big  markets  because 
the  goods  must  measure  up  to  the  highest  standards 
of  all  other  sections  of  the  country.  The  best  of  every- 
thing is  shipped.  The  sweets  must  not  only  be' the  best 
of  their  variety,  but  the  variety  itself  must  be  of  the 
kind  in  popular  favor.  Most  of  the  larger  markets 
give  preference  to  certain  standard  varieties,  which,  al- 
though perhaps  not  so  good  as  some  other  kinds,  are 
most  popular  because  of  prestige  gained  through  years 
of  continued  appearance.  To  change  such  varietal 
market  demands  is  a  problem  of  judicious  advertising 


246  The  Sweet  Potato 

requiring  years  of  faithful  and  patient  cultivation. 
The  g-rowers  of  the  South  are  now  making  united  efforts 
to  gain  for  their  more  juicy  "  yam  "  varieties  prestige 
in  the  northern  and  western  markets  over  the  dry- 
fleshed  Nansemond  kinds,  which  at  the  present  rank 
first  in  commercial  demand.  In  shipping  to  foreign 
markets,  considerable  skill  is  necessary  in  making  ar- 
rangements for  the  loading  and  handling  of  cars,  and  if 
sold  personally  by  the  shipper  on  the  city  markets,  the 
necessary  trackage  and  warehouse  space  must  be  pro- 
vided when  large  shipments  are  involved.  When  ex- 
tensive shipments  are  being  made,  the  services  of  a 
specialist  who  has  made  a  study  of  these  conditions  may 
be  necessary.  Growers  are  often  unfair  in  their  ex- 
pectations of  the  home  markets.  They  frequently  ask 
the  grocer  as  much  for'  their  potatoes  as  they  would 
expect  directly  from  the  consumer.  If  there  is  any  sur- 
plus to  be  shipped,  it  usually  consists  of  the  best  and 
the  net  retvirns  are  often  less  than  received  on  the  home 
market  for  goods  of  inferior  quality.  Home  markets 
everywhere  are,  generally  speaking,  capable  of  being  de- 
veloped materially  above  their  present  status. 

Advertising. 

Although  having  no  effect  on  seasonal  distribution, 
advertising  does  have,  and  with  sweet  potatoes  will  con- 
tinue to  have  an  ever-increasing  influence  on  territorial 
distribution.  There  is  a  large  field  of  consumption  yet 
to  be  opened  up  in  new  territories  where  the  best  quality 
of  sweet  potatoes  is  now  unknown.  This  will  only 
be  accomplished  by  advertising  in  one  way  or  another. 
"  Sunkist  "  oranges  have  been  made  famous  by  advertis- 
ing, as  well  as  scores  of  other  articles  too  numerous  .to 


Commercial  Disposal  of  the  Siveet  Potato       247 

mention.  Advertising  is  sure  to  play  a  very  prominent 
part  in  the  future  development  of  our  sweet  potato 
marketing  system. 

An  attractive  trade  label  is  one  of  the  most  efficient 
and  convenient  advertising  mediums  at  hand  with  the 
sweet  potato  grower.  These  can  be  printed  on  paper 
and  pasted  on  the  market  container,  or  they  may  be 
stenciled  or  printed  directly  on  the  container  itself. 
Many  growers  have  found  small  printed  circulars,  which 
were  placed  in  each  package,  to  be  highly  profitable. 
These  usually  tell  what  variety  is  represented,  how, 
where,  and  by  whom  the  potatoes  were  grown,  and  they 
may  contain  some  new  or  desirable  cooking  re'cipes.. 
Advertising  is  sometimes  inserted  in  the  standard  fruit 
and  vegetable  journals  or  papers. 

SELI.ING    AGEiNCIES 

Sweet  potatoes  may  be  sold  on  local  markets  as  already 
discussed ;  through  the  medium  of  a  commission  house ; 
cooperative  marketing  association ;  or  by  direct  personal 
sale  to  individuals  or  firms  in  distant  markets. 

Commission  house. 

Doubtless  the  oldest  and  best  known  method  of 
selling  sweet  potatoes  in  the  United  States  is 
through  the  medium  of  the  commission-man.  Long 
before  cooperative  marketing  was  given  any  serious 
thought  by  southern  farmers,  the  commission-man 
was  at  hand  to  sell  their  produce  for  a  specified 
toll  out  of  thee  gross  receipts.  ]\Iany  of  the  larger 
commission  firms  have  sent  out  traveling  agents  who 
made  it  their  business  tO'  locate  centers  of  produc- 
tion  and    endeavor   to   get   growers    to   ship    to   their 


248  The  Sweet  Potato 

firm.  The  policy  of  these  men  has  been  to  solicit  ship- 
ments direct  to  the  house  on  the  basis  of  prevailing 
markets  at  time  of  arrival  rather  than  to  quote  anj 
price  in  advance.  Commission-men  have  been  severely 
criticized  at  times  as  unnecessary  middle-men.  In 
former  years  much  of  this  criticism  was  brought  on 
by  unscrupulous  dealers  who  did  not  give  their  cus- 
tomers honest  service.  Public  opinion  and  sounder 
business  principles  have  done  much  to  discourage  dis- 
honest practice,  however,  and  the  commission-man  has 
greatly  simplified  the  farmers'  marketing  problem  and 
no  good  way  has  yet  been  found  to  eliminate  him  from 
the  selling  program. 

In  selling  through  commission  firms,  the  first  step 
is  to  learn  the  names  of  reliable  houses  in  the  nearest 
markets.  It  would  be  well  to  write  the  firm  several 
weeks  before  shipping  season  aaid  find  out  how  many 
potatoes  they  can  use  a  day  or  a  week,  and  their  terms. 
It  would  be  wise  to  get  in  touch  with  several  firms  in 
the  respective  big  markets  in  this  way.  Daily  Market 
Report  sheets,  which  give  the  prevailing  prices  in  each 
leading  market  for  that  day,  may  be  obtained  free  of 
charge  from  the  nearest  office  of  the  Bureau  of  Markets. 
These  should  be  watched  each  day.  Though  they  do  not 
tell  what  a  given  carload  of  potatoes  will  bring  a  pound 
or  a  bushel,  they  report  prices  on  the  actual  sales  which 
took  place  during  the  day  and  thus  give  a  very  clear 
indication  of  the  tendency  of  prices  in  the  various  city 
markets.  One  or  two  days  before  the  grower  is  ready 
to  load  his  car,  he  should  wire  one  of  the  commission- 
men  with  whom  he  has  been  corresponding,  who  lives  in 
the  particular  city  where  prevailing  prices  seem  to  be 
best  as  indicated  by  his  Market  Report  Sheet  at  the 


Commercial  Disposal  of  the  Sweet  Potato       249 

time  he  is  ready  to  ship.  In  the  telegram  the  grower 
will  ask  whether  the  commission-man  can  handle  a  cer- 
tain number  of  cars  of  a  particular  variety,  packed  in  .a 
given  container,  loaded  at  a  certain  point  on  a"  given 
day.  The  commission-man  will  investigate  his  order 
for  that  time,  caleuhite  the  time  it  will  take  the  potatoes 
loaded  at  the  given  point  to  reach  him  and  will  advise 
the  shipper  whether  or  not  he  can  handle  them,  at  that 
time.  It  may  happen  that  he  is  already  expecting  the 
arrival  of  several  cars  from  other  points  at  that  time 
and  cannot  handle  the  potatoes  then,  bnt  would  like  to 
have  them  a  few  days  later.  When  he  advises  the 
grower  to  this  effect  (by  telegraph),  the  latter  may  be 
afraid  to  wait  until  that  time  for  fear  prices  will  fall 
or  for  some  other  reason.  In  this  event  he  immediately 
tries  another  firm  in  the  same  manner.  The  Market 
Report  sheets  always  indicate  the  demand  and  rate  of 
movement  in  the  various  cities  and  if  these  reports  are 
promptly  acted  on,  there  will  never  be  any  difficulty  in 
finding  some  firm  in  the  strongest  market  who  can  han- 
dle the  shipment.  It  may,  however,  happen  that  some 
one  house  is  over-supplied  at  that  time. 

An   example   of   the   information   contained   in   the 
Market  Report  sheets  is  as  follows : 

UNITED  STATES  DEPARTMENT  OF  AGRICULTURE 

Bureau  of  Markets 

Daily  Market  Report 

Memphis,  Tenn.  Rooms  601-03  Exchange  Bldg. 

Feb.  15,  1919.  Telephone  —  Main  796 

No.  128 

SWEET  POTATOES 

Reports  by  direct  leased  wire  from  important  markets. 

This  morning's   sales   unless   otherwise   reported. 

Chicago:     32°  Snowing.     1  Tenn.  arrived.     2  cars  on  track 


350  The  Sweet  Potato 

including  broken.  Demand  and  movement  good,  little 
change  in  price.  Sales  to  jobbers,  Tenn.  bushel  hampers, 
Nancy  Halls,  quality  and  condition  generally  good,  2.50- 
2.65,  mostly  2.65. 

St.  Louis:  28°  Snowing.  4  Tenn.,  1  Ga.,  1  Fla.  arrived;  7 
ears  on  track,  demand  and  movement  slow,  prices  sliglitly 
lower,  quality  and  condition  good,  few  decayed.  Sales  to 
jobbers,  Tenn.  bushel  hampers,  Nancy  Halls,  repacked, 
mostly  2.45-2.55.  Georgias,  bushel  crates  red  varieties, 
quality  and  condition  ordinary,  slightly  decayed,  1.75-2.10. 
Florida  cloth  top  stave-barrels,  yellow  varieties,  wide  range 
in  quality  and  condition,  5.00-5.75. 

Cincinnati:  23°  Snowing.  2  Ala.  4  Va.  arrived.  9  cars  on 
tracks  including  broken.  Supplies  heavy,  movement  drag- 
ging, little  change  in  price.  Sales  to  jobbers,  quality  and 
condition  generally  good.  North  Carolinas,  barrel  crates, 
Nancy  Halls,  and  Southern  Queens,  5.75-6.2*5.  Seed: 
Virginia  cloth  top  stave  barrels,  Big  Stem  Jersey  7.00. 
Delawares,  bushel  hampers,  Big  Stem  Jersey,  2.75,  few 
3.00.     Alabama  bushel  crates  2.40-2.65. 

Some  growers  prefer  to  have  government  inspection 
when  the  car  arrives  at  destination,  which  can  be  secured 
for  $2.50  a  car  on  request.  The  report  of  the  govern- 
ment inspector  stands  as  conchisive  evidence  in  any 
court  of  the  United  States  should  a  suit  arise  concerning 
the  condition  of  the  potatoes  on  arrival.  The  inspector 
makes  four  copies  of  his  report ;  one  is  kept  on  file ;  the 
shipper  and  receiver  are  each  supplied  with  one;  and 
one  copy  is  sent  to  Washington  to  be  kept  on  file  there. 

From  5  to  10  per  cent  of  the  gross  sales  is  usually  the 
commission  charged.  After  being  sold,  the  commission 
is  deducted  from  the  gross  sales,  the  freight  and  drayago 
is  then  subtracted,  and  a  check  for  the  balance  is  sent  the 
grower.  Receipts  for  freight  and  all  other  money  paid 
out  by   the  commission-man   on  the  producer's   goods 


Commercial  Disposal  of  the  Sweet  Potato       351 

should  be  sent  the  latter  with  the  check  for  his  net 
returns. 

As  has  been  said,  the  grower  should  never  lose  an 
opportunity  to  become  personally  acquainted  with  the 
commission-man  who  handles  his  goods.  Personal  ac- 
quaintance will  be  mutually  profitable.  The  ]!^ational 
League  of  Commission  Merchants  will  give  information 
concerning  the  reliability  of  any  leading  commission- 


Cooperative  shipping. 

Intensification  of  state  cooperative  extension  work 
from  the  land  grant  colleges  has  done  much  to  stimulate 
cooperation  in  all  lines  of  farming  and  especially 
cooperative  shipping  of  perishable  truck  crops.  Local 
agricultural  agents  in  each  county  to  notify  the  farm- 
ers of  the  day  designated,  with  a  state  marketing 
specialist  to  place  the  cars,  have  greatly  facilitated 
cooperative  shipping  of  sweet  potatoes  throughout  the 
southern  states,  where  the  sweet  potato  industry  as  a 
commercial  enterprise  is  comparatively  young,  and 
where  many  of  the  farmers  know  nothing  of  marketing 
principles. 

The  only  way  in  which  an  organized  coopera- 
tive association  can  be  formed  successfully  among 
farmers  is  for  a  specific  and  urgent  need  to  exist  for 
cooperative  effort  in  order  that  some  one  thing  of  com- 
mon interest  may  be  accomplished.  The  need  must  be 
immediate.  Frequently  when  some  outside  agency  has 
helped  a  number  of  growers  to  get  together  to  ship  a 
car  of  potatoes  cooperatively,  the  need  for  an  organiza- 
tion will  be  recognized.  Much  has  been  said  and  writ- 
ten about  cooperation  within  the  last  few  years,  some 


252  The  Sweet  Potato 

of  which  has  been  practical  and  some  more  or  less  imag- 
inary. Cooperation  through  the  Eastern  Shore  of  Vir- 
ginia Produce  Exchange  has  made  New  Jersey,  Dela- 
ware and  Virginia  famous  for  their  superior  Nanse- 
mond,  or  Jersey  Sweets.  Cooperation,  through  the 
efforts  of  the  Georgia  Sweet  Potato  Growers  Associa- 
tion, has  made  Tennessee  Nancy  Halls  known  and  de- 
manded throughout  this  country.  The  good  work  of 
similar  organizations  could  be  cited  in  other  states. 
The  method  of  forming  a  cooperative  shipping  associa- 
tion will  depend  entirely  on  local  conditions,  ability  of 
the  leaders,  and  the  amount  of  sweet  potatoes  to  be 
marketed.  A  good  leader  with  experience  and  well 
formed  plans  who  possesses  the  personality  and  execu- 
tive ability  to  carry  them  out  is  an  essential  constituent 
of  the  association  that  succeeds.  Cooperative  shipping 
associations  are  non-profit-sharing  in  character,  and  usu- 
ally meet  their  current  operating  expenses  by  levying  a 
certain  tax  on  each  package  or  bushel  of  potatoes  sold. 

SELLING    METHODS 

The  individual  method  of  keeping  in  touch  with  mar- 
kets and  selling  through  commission  firms,  just  now 
discussed,  treats  in  general  the  methods  used  by  any 
selling  agency.  Exchanges  or  large  cooperative  ship- 
ping associations  may  do  sufficient  business  to  justify 
them  in  keeping  a  salaried  salesman  in  the  big  markets 
during  the  shipping  season.  This  is  supposed  to  be  de- 
sirable in  some  instances,  because  regular  salaried 
agents  of  the  association  call  on  the  trade  from  time  to 
time  and  solicit  their  business  for  the  particular  kind 
of  brand  of  potatoes  which  the  organization  has  for 
sale  and  is  trying  to  establish  on  the  market.     The  ad- 


Commei'cial  Disposal  of  the  Sweet  Potato       253 

vantages  of  such  work  are  obvious.  As  sweet  potato 
shipping  associations  become  more  numerous  and  better 
organized,  the  commission  house  will  be  less  used.  The 
employment  of  a  special  salesman  is,  however,  a  heavy 
expense  which  the  greater  number  of  small  associations 
cannot  afford  to  bear,  and  different  substitutes  for  such 
a  representative  have  been  tried.  Theoretically,  if  a 
large  number  of  separate  associations  had  their  special 
salesmen  on  the  markets,  they  would  eventually  be  com- 
peting against  each  other  and  thus  defeat  the  original 
principles  of  cooperation.  This  condition  wouhl  be 
likely  to  occur  more  quickly  with  an  association  handling 
only  one  commodity.  Instead  of  employing  salaried 
salesmen,  some  associations  have  merely  agreed  with 
some  standard  selling  agency  in  the  market  to  handle 
all  of  their  output.  Such  an  agency  might,  of  course, 
make  similar  agreements  with  any  number  of  other 
associations.  It  is  possible  that  as  the  sweet  potato 
industry  grows,  centralized  distributing  associations 
will  eventually  be  established  in  the  big  cities  which 
will  handle  the  business  of  a  large  number  of  associa- 
tions and  exchanges  all  over  the  country.  At  present 
the  exchanges  either  handle  their  sales  direct  or  sell  them 
to  various  firms  already  on  the  market. 

Track  and  f.  o.  b.  sales. —  Perhaps  the  most  satis- 
factory method  of  selling  sweet  potatoes  is  to  contract 
them  to  a  reliable  firm  for  a  specified  price  delivered 
free  on  board  the  cars.  This  relieves  the  grower  of  any 
further  responsibility,  does  not  require  him  to  wait  for 
his  money,  and  when  a  sufficient  shipment  is  being  made 
to  attract  the  buyer  to  the  loading  point,  better  net 
returns  are  frequently  received.  A  track  sale  means 
selling  the  potatoes  at  the  car  on  the  track  nearest  the 


254  The  Siveet  Potato 

point  of  production.  An  f.  o.  b.  sale  may  specify  that 
the  potatoes  are  to  be  delivered  free  on  board  at  any 
point  that  may  be  agreed  on.  The  terms  are,  however, 
very  closely  related  and  are  often  used  interchangeably. 

Open  consignment. —  When  a  commission  firm  is  well 
known,  the  usual  method  of  selling  is  merely  to  bill  the 
car  to  the  firai  in  question  on  open  account.  Buyers 
frequently  claim  that  they  can  handle  goods  to  better  ad- 
vantage when  shipped  in  this  way.  The  original  re- 
ceivers in  the  big  markets  usually  resell  to  jobbers. 
Jobbing  houses  have  been  referred  to  as  the  food  banks 
of  the  country.  They  buy  from  the  original  receivers 
or  commission  merchants  and  resell  to  the  retail  stores 
of  the  country,  who  in  turn  pass  the  goods  on  to  the  con- 
sumers. Commission  merchants  prefer  having  sweet 
potatoes  shipped  to  them  on  open  account  because  it 
requires  less  immediate  outlay  of  capital,  and  at  the 
same  time  gives  them  all  the  privileges  of  complete 
ownership  in  selling  to  the  jobbers  or  other  buyers.  If 
the  reliability  of  the  person  to  whom  the  grower  orig- 
inally consigns  the  goods  is  not  known,  however,  it  is 
best  to  have  some  kind  of  a  check  on  his  actions. 

Bill  of  lading  attached. —  The  shipment  of  sweet 
potatoes  bill  of  lading  attached  is  the  method  followed 
by  a  large  number  of  small  associations  that  have  been 
remarkably  successful  in  the  collection  of  all  their 
accounts.  The  car  of  potatoes  is  billed  direct  tO'  a 
buyer.  A  sight  draft  covering  the  price  of  the  contents 
of  the  car  is  attached  to  the  bill  of  lading  and  goes  with 
it.  A  copy  of  this  bill  is  at  the  same  time  sent  to  the 
bank  which  handles  the  buyer's  business.  The  railroad 
then  protects  the  seller  by  requiring  the  buyer  to  go  to 
his  bank  and  take  up  the  attached  bill,  which  automati- 


Commercial  Disposal  of  the  Sweet  Potato       255 

callj  becomes  a  sight  draft,  and  after  being  paid  becomes 
a  receipted  bill.  The  buyer  then  presents  his  receipted 
bill  to  the  railroad  company,  which  turns  over  his  car- 
load of  potatoes.  No  credit  is  extended,  no  room  is  left 
for  fraud,  and  the  seller  receives  his  money  immediately. 
When  business  is  done  in  this  way,  the  seller  must  play 
the  game  fairly  and  stand  squarely  behind  his  goods  and 
his  selling  price.  If  the  goods  do  not  measure  up  to 
what  they  were  bought  for,  he  should  make  the  deficiency 
good. 

Miscellaneous  metliods. —  Sweet  potatoes  are  fre- 
quently sold  to  a  considerable  extent  by  direct  sale  to 
consumers  in  different  parts  of  the  country.  This  is 
a  favorite  way  of  selling  seed  stock.  Usually  adver- 
tisements are  run  in  the  classified  columns  of  numerous 
farm  journals  and  the  goods  are  shipped  by  express  or 
freight  direct  to  the  buyer.  To  avoid  handling  a  large 
number  of  small  accounts,  the  seller  usually  requires  the 
order  to  be  accompanied  by  the  purchase  price.  A 
mode  of  selling  sweet  potatoes  which  has  recently  come 
into  use  on  the  markets,  but  with  which  the  grower  has 
no  connection,  is  through  the  fruit  auction  companies. 
Carload  lots  of  specified  grade,  variety  and  character 
are  sold  to  highest  bidders.  These  auction  companies 
are  usually  profit-sharing  corporations.  Growers  never 
consign  cars  directly  to  an  auction  company,  they  are 
always  sent  to  some  agent,  who  may  turn  them  over  to 
the  auction  company  if  the  shipper  so  desires.  If  the 
car  is  a  cooperative  shipment,  a  manifest  of  the  contents 
of  the  car,  giving  the  name  of  each  contributor  and  the 
quality,  variety  and  grade  which  it  contained,  is  made  in 
duplicate,  one  copy  being  sent  to  the  agent  and  the  other 
to  the  auction  company.     The  manifest  should  be  sent 


256  The  Sweet  Potato 

to  arrive  the  day  before  the  car,  so  it  may  be  properly 
catalogued.  Sweet  potatoes  sold  at  auction  are  usually 
inspected  in  the  car,  rather  than  sold  from  samples  as 
with  many  fruits. 


INDEX 


Aceto-arsenite  of  copper,  171 

Acid  phosphate,  102 

Acreage  in  United  States,  13 

Advertising,  88,  246 

Agnes,  sweet  potato  a  la,  50 

Air-ventilated  cars,  230 

Ajes,  5 

Albvgo  ipomo'CE-pandurancB,  164 

Alcohol  manufacture,  41 

Amates,  5 

Ammonia,  100 

Analysis  of  feeding  stuffs,  27 

of  tubers  and  vines,  20 

of  vines,  33 
Anguilla,  122 
Argus  tortoise  beetle,  142 
Arkansas  Beauty,  122 
Arsenate  of  lead,  170 
Arsenite  of  lime,  171 
Ashes,  hardwood,  103,  111 

Baked  sweet  potato  custard,  50 

sweet  potatoes,  47 
Banking,  203 
Barrel  pumps,  174 
Barrels  for  shipping,  215 

packing  of,  233 
Barrett,  J.  H.,  and  Son,  quoted, 

45 
Batatas,  5 

edulis,  5 
Beattie,  cited,  31 
Beattie,  J.  H.,  cited,  121 
Bedding,  73 
Beds  for  planting,  62 
Bejuco  de  puerco,  6 
Big  Stem  Jersey,   122 
Bill  of  lading  sales.  254 
Biscuit,  sweet  potato,  48 
Black-leaf -40,  172 


Black-legged  tortoise  beetle,  140 
Black-rot,  160 

Java,  166 
Black-shank,  160 
Black  Spanish,  123 
Blanca,  120 
Blue-stem,   156 
Boiled  sweet  potatoes,  51 
Bordeaux  mixture,   173 
Botanical  classification,  5 
Brazilian,  123 
Bread,  sweet  potato,  48 
Brehm,  C.  E.,  quoted,  124 
Bretschneider,  quoted,  1 
Browned  sweet  potatoes,  47 
Bunch,  134 

Camote,  5 
Camotes,  5 

Candied  sweet  potatoes,  48 
Canned  sweet  potatoes,  45 
Carbon  bisulfid,   173 
Cars  for  shipping,  230 
Carver,  G.  W.,  cited,  30,  39,  83 
Cassida  bivittata,  140 

nifjripes,  140 
Chaetocnema  confinis,  137 
Charcoal-rot,  167 
Chelymorpha  argus,   142 
Chips,  39 

Chittenden,  F.  H.,  quoted,  116 
Chlorids,  102 
Classification,  5 
Climatic  requirements,  16 
Clusius,  cited,  2,  5 
Coldframes,  65 
Collins,  quoted,  6 
Commercial  disposal,  238 

fertilizers,   103 

plant  business,  85 


258 


Index 


Commission  house,  247 

-man.  247 
Composition  of  Irish  potato,  22 

of  sweet  potato,  21 
Compressed  air  sprayers,  174 
Containers,  212 
Convoliithis  Batatas,  5 
Cook,  quoted,  6 
Cookies,  sweet  potato  drop,  51 
Cookinfi  of  sweet  potatoes,  46 
Cooperative    shipping,    251 
Coptocycia  hicolor,  141 

sif/nifera,  142 
Cotton-seed  meal,  100,  101 
Crates  for  shipping,  218 

packing  of,  236 
Creola,  123 
Cultivation,  93 

Curing-houses,  commercial,  202 
Custard,  baked  sweet  potato,  50 
Cylas  formicarius,  145 

DeCandolle,  cited,  2,  5 

Dehydrated  sweet  potatoes,  34 

Delaware,  124 

Description,  3 

Desiccated  sweet  potatoes,  34 

Devil's  food,  sweet  potato,  50 

Diaporthe  batatatis,  166 

Dioscorea,  6 

Diplodia  tnhericola,  166 

Disease,  selection  of  seed  for,  57 

treatment  of  seed-bed  for,  79 
Diseases,  155 

influence  of  rotation  on,  115 
Distribution,  10 
Domestic  animals,  food  for,  25 

cooking,  46 
Dooley  Yam,  123 
Drawing  tlie  plants,  80 
Draws,  ])ropagation  by,  54,  80 
Dried  blood,  100 

sweet  potatoes,  35 
Drop  cookies,  sweet  potato,  51 
Dry-rot,  160 
Dusters,  175 

East  Texas  Yam,  125 
Excretions  from  roots,  114 


Facing,  228 

Feeding  stuffs,  analysis  of,  27 

Fertilizers,  96 

Fish  scrap,  100 

Fitz,  Jas.,  cited,  84 

Flea-beetle,  137 

Florida  Yam,  124 

Flour,  sweet  potato,  38,  51 

Flowers,  description  of,  4 

F.  o.  b.  sales,  253 

Food  for  domestic  animals,  25 

for  man,  21 

value,  21 
Foot-rot,  158 
Foreign  markets,  243 
Fried  sweet  potatoes,  47 
Fullerton  Yellow  Yam,  124 
Fungicides,  170 
Fii sarin m  batatatis,  156 

hyperoxysporum,  156 

General  Grant,  124 
Georgia  Buck,  125 

Yam,  125 
Gold -bugs,  139 
Gold  dust,  172 
Golden  tortoise  beetle,  141 
Gold  Skin,  124 
Grading,  223 
Green-manures,  109 

Hampers  for  shipping,  217 

packing  of,  235 
Hardenin'g-off,   79 
Hardwood  ashes,  103,  HI 
Harvesting,  177 
Hayman,  125 
Henry,  cited,  27 

and  Morrison,  cited,   114 
High,  M.  M.,  cited,  151 
Home  markets,  241 

-mixing  fertilizers,  105 
Hotbed,  Ihie-lieated,  69 

manure-lieated,  67 

pi])e-heatod,  71 
House,  (juoted,  5 
Humboldt,  cited,  5 
Humus,  108 


Index 


259 


Insecticides,  170 
Insects,  137 

influence  of  rotation  on,  115 
Ipomrra  Batatas,  5 

fastiffiata.  G 
Irish  potato,  composition  of,  22 
Irrigation,  96 

Java  black-rot,  1G6 
Jersey  mark,   102 

Sweet,   12S 
Jewel  Yam,  12fi 

Johnson,  T.  C.  quoted,  7fi,  122, 
123,  125,  126,  129,  130,  132, 
134,  135 


IMineral  phosphates,  101 
Mottled  tortoise  beetle,  142 
Muck,  HI 

Muffins,  sweet  potato,  49 
Murates,  102 

Nancy  Hall,    128 
Nansemond,  128 
Nicotine  sulfate,  172 
Nigger  Choker,  12fl 

Killer,  129 
Nitrate  of  ammonia,  101 
Nitrates,  101 
Nitrogen,  100 
Norton  Yam,  129 


Kainit,  103 

Keeping,  180 

Keitt,  T.   E.,  cited,  20,  27,  32, 

40,  133,  134 
Key  West  Yam,  126 
Knapsack  pumps,  174 


Old  Fashioned  Yellow  Yam,  129 
Old  Spanish  variety,  133 
Open  beds,  64 

consignment,  254 
Organic  nitrogen,  100 
Ozonium  omnivorum,  159 


Lang^vorthy,  C.  F.,  quoted,  24 
Laundry  soap,  172 
Leaf-blight,  163 

-eaters,  139 

-mold.    111.   164 

-spot,  103 
Legal  wei->ht,  213 
Lime,  llT 
Little  Stem  Jersey,  127 

]\Tameyita,  120 
Mameyona,   120 
Man,  food  for.  21 
Manufactured  products,  33 
Manure,  110 
Marketing,  207,  238 
Market  preparation,  207 

Report  Sheet,  249 

requirements,  207 
Markets,  240 

foreign,  243 

liome,  241 
Meyers  Early,  128 
Miller,  E.  A.,  quoted.  84 
Miller.  Fred  E.,  quoted,  71,  90, 
106,  116,  118,  127 


Packages,  213 
Packing,  226 
Paris  green,  171 
Peabody,  129 

Peanut    croquettes,    sweet    po- 
tato. 49 
Peat,   111 
Phosphates,   101 
Phosphorus.  101 
Phyllnstirta   batatas,  163 
Pie  product,  38 
Pierso)).  130 
Plant-bed,   02 

Plant  business,  commercial,  85 
Planting,  91 

preparation  for,  90 
Plowdomvs  destruens,   158 
Poison  bran  mash,  172 
Polo,   130 
Porto  Rico.  130 
Potash,  102 
Poultry  manure.  111 
Power  outfits,  175 
Preparation  for  market,  207 

for  planting,  90 
Price,  J.  C.  C,  quoted,  69 


260 


Index 


Pride  of  Kansas.  131 
Production  in  Unitod  States,  11 

of  seed  potatoes,  GO 
Propajration,  54 
iPumpkin  Yam,  131 
Purple  Yam,  130 

Quality  of  product,  222 
Quantity  to  produce,  225 

Raisins       and       marshmallows, 

sweet  potatoes  with,  50 
Recipes  for  cooking,  47 
Red  Bermuda,  131 

Brazil,  132 

Carolina,   132 

Jersey,  132 

Nansemond,  132 

Nose,  132 
Refrifrerator  cars,  230 
Requirements  for  market,  207 
Rhizopus  nigricans,  165 
Riced  sweet  potatoes,  51 
Riley,  C.  v.,  cited,  U3 
Ring-rot,  leS^.^f*-'     . 
Root  excreti'6nst"ll4 
Root-r^^rlSO     ; 
Rosts,'  as  food  .ff)r  animals,  30 
Rosa,  J..  T..  quoted,  76,  122 
RotfitJori,  112 
Rots,  control  of,  167 
Ruktaln,  6 
Rust,  162 


Sacks  for  shipping,  214 

packing  of,  235 
Salad,  sweet  potato,  49 
Saw-flies,  143 
Schisocervs  cbenus,  144 

privatus,  144 
Sclerotium  hataticfola,  167 
Scott,  J.  M.,  quoted,  29 
Scurf,  162 

Seed-beds,  covering  for,  75 
Seed,   description   of,   4 

potatoes,  production  of,  60 

selection  of,   56 
Selecting  seed,  56 


Selling,  238 

agencies,  247 

methods,  252 
Septoria  bataticola,  163 
Setting  plants,  92 
Shanghai,  132 
Shanghor  Yam,  133 
Silage,  28 

Simpson,  Cornelia,  cited,  46 
Sirup  from  sweet  potatoes,  42 
Sliced    and    baked    sweet   pota- 
toes, 51 
Soft-rot,  165 
Soil-splotch,  162 

stain,  102 

types,  16 
Southern  Queen,  125 
SpJiacronema  fimhriatum,  160 
Split-Leaf  Yam,  125 
Spray  machinery,  174 
Stable-manure,    110 
Starch  manufacture,  39 

sweet  potato,  53 
Stem-rot,   156 
Storage,  179 

Storage-house,    advantage    over 
bank,  185 

construction  of,  189 

operation  of,  198 

outbuildings  for,  201 
Storage  rots,  control  of,  167 
Sugar,  39 
Sulfates,  102 
Superphosphates,  102 
Sylvinit,  103 

Tankage.  100 

Temperature  of  plant-bed,  77 
Tennessee  Notchleaf,  133 
Texas  root-rot,   159 
Thompson,  quoted,  203 
Tillage,  90 

Tobacco  decoction,  172 
Tolman,  133 
Tortoise  beetles,  139 
Track  sales,  253 
Transit,  229 
Transportation,  229 
Triumph,  133 


Index 


261 


Tubers  and  vines,   analysis   of, 
20 
description  of,  4 
Turpin,  cited,  2 

Two-striped  sweet  potato  beetle, 
140 


Utilization,  20 


Value  in  United  States 
Varieties,  120 
Vine-cuttings,  S2 
Vineless  Bunch  Yams,  134 
Vines,  analysis  of,  33 

for  hay,  32 
Watering  of  plant-bed,  78 


11 


Weeds,  influence  of  rotation 

115 
Weevil,   145 
Weight,  legal,  213 
White  Barbadoes,  134 

Belmont,    134 

-rust,  164 

Spanish,  134 

Yam,  134 
Wilt,  156 

Yam.  origin  of  word,  6 
Yellow  Barbadoes,  135 

Belmont.  135 

iSTansemond.  135 

Strasburg.   135 
Yield  to  the  acre,  9 


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